all: switch gas limits from big.Int to uint64

82 files changed, 606 insertions, 642 deletions

diff --git a/accounts/abi/bind/backend.go b/accounts/abi/bind/backend.go
index 25b61928e..a7ca7bfc0 100644
--- a/accounts/abi/bind/backend.go
+++ b/accounts/abi/bind/backend.go
@@ -85,7 +85,7 @@ type ContractTransactor interface {
 	// There is no guarantee that this is the true gas limit requirement as other
 	// transactions may be added or removed by miners, but it should provide a basis
 	// for setting a reasonable default.
-	EstimateGas(ctx context.Context, call ethereum.CallMsg) (usedGas *big.Int, err error)
+	EstimateGas(ctx context.Context, call ethereum.CallMsg) (gas uint64, err error)
 	// SendTransaction injects the transaction into the pending pool for execution.
 	SendTransaction(ctx context.Context, tx *types.Transaction) error
 }
diff --git a/accounts/abi/bind/backends/simulated.go b/accounts/abi/bind/backends/simulated.go
index 2cf6b9f78..81c32e421 100644
--- a/accounts/abi/bind/backends/simulated.go
+++ b/accounts/abi/bind/backends/simulated.go
@@ -200,7 +200,7 @@ func (b *SimulatedBackend) SuggestGasPrice(ctx context.Context) (*big.Int, error
 
 // EstimateGas executes the requested code against the currently pending block/state and
 // returns the used amount of gas.
-func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMsg) (*big.Int, error) {
+func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMsg) (uint64, error) {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
@@ -210,16 +210,16 @@ func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMs
 		hi  uint64
 		cap uint64
 	)
-	if call.Gas != nil && call.Gas.Uint64() >= params.TxGas {
-		hi = call.Gas.Uint64()
+	if call.Gas >= params.TxGas {
+		hi = call.Gas
 	} else {
-		hi = b.pendingBlock.GasLimit().Uint64()
+		hi = b.pendingBlock.GasLimit()
 	}
 	cap = hi
 
 	// Create a helper to check if a gas allowance results in an executable transaction
 	executable := func(gas uint64) bool {
-		call.Gas = new(big.Int).SetUint64(gas)
+		call.Gas = gas
 
 		snapshot := b.pendingState.Snapshot()
 		_, _, failed, err := b.callContract(ctx, call, b.pendingBlock, b.pendingState)
@@ -242,21 +242,21 @@ func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMs
 	// Reject the transaction as invalid if it still fails at the highest allowance
 	if hi == cap {
 		if !executable(hi) {
-			return nil, errGasEstimationFailed
+			return 0, errGasEstimationFailed
 		}
 	}
-	return new(big.Int).SetUint64(hi), nil
+	return hi, nil
 }
 
 // callContract implemens common code between normal and pending contract calls.
 // state is modified during execution, make sure to copy it if necessary.
-func (b *SimulatedBackend) callContract(ctx context.Context, call ethereum.CallMsg, block *types.Block, statedb *state.StateDB) ([]byte, *big.Int, bool, error) {
+func (b *SimulatedBackend) callContract(ctx context.Context, call ethereum.CallMsg, block *types.Block, statedb *state.StateDB) ([]byte, uint64, bool, error) {
 	// Ensure message is initialized properly.
 	if call.GasPrice == nil {
 		call.GasPrice = big.NewInt(1)
 	}
-	if call.Gas == nil || call.Gas.Sign() == 0 {
-		call.Gas = big.NewInt(50000000)
+	if call.Gas == 0 {
+		call.Gas = 50000000
 	}
 	if call.Value == nil {
 		call.Value = new(big.Int)
@@ -271,9 +271,9 @@ func (b *SimulatedBackend) callContract(ctx context.Context, call ethereum.CallM
 	// Create a new environment which holds all relevant information
 	// about the transaction and calling mechanisms.
 	vmenv := vm.NewEVM(evmContext, statedb, b.config, vm.Config{})
-	gaspool := new(core.GasPool).AddGas(math.MaxBig256)
-	ret, gasUsed, _, failed, err := core.NewStateTransition(vmenv, msg, gaspool).TransitionDb()
-	return ret, gasUsed, failed, err
+	gaspool := new(core.GasPool).AddGas(math.MaxUint64)
+
+	return core.NewStateTransition(vmenv, msg, gaspool).TransitionDb()
 }
 
 // SendTransaction updates the pending block to include the given transaction.
@@ -328,6 +328,6 @@ func (m callmsg) Nonce() uint64        { return 0 }
 func (m callmsg) CheckNonce() bool     { return false }
 func (m callmsg) To() *common.Address  { return m.CallMsg.To }
 func (m callmsg) GasPrice() *big.Int   { return m.CallMsg.GasPrice }
-func (m callmsg) Gas() *big.Int        { return m.CallMsg.Gas }
+func (m callmsg) Gas() uint64          { return m.CallMsg.Gas }
 func (m callmsg) Value() *big.Int      { return m.CallMsg.Value }
 func (m callmsg) Data() []byte         { return m.CallMsg.Data }
diff --git a/accounts/abi/bind/base.go b/accounts/abi/bind/base.go
index b40bd65e8..2bd683f22 100644
--- a/accounts/abi/bind/base.go
+++ b/accounts/abi/bind/base.go
@@ -50,7 +50,7 @@ type TransactOpts struct {
 
 	Value    *big.Int // Funds to transfer along along the transaction (nil = 0 = no funds)
 	GasPrice *big.Int // Gas price to use for the transaction execution (nil = gas price oracle)
-	GasLimit *big.Int // Gas limit to set for the transaction execution (nil = estimate + 10%)
+	GasLimit uint64   // Gas limit to set for the transaction execution (0 = estimate)
 
 	Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
 }
@@ -189,7 +189,7 @@ func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, i
 		}
 	}
 	gasLimit := opts.GasLimit
-	if gasLimit == nil {
+	if gasLimit == 0 {
 		// Gas estimation cannot succeed without code for method invocations
 		if contract != nil {
 			if code, err := c.transactor.PendingCodeAt(ensureContext(opts.Context), c.address); err != nil {
diff --git a/accounts/abi/bind/bind_test.go b/accounts/abi/bind/bind_test.go
index 896441d79..b56477e0c 100644
--- a/accounts/abi/bind/bind_test.go
+++ b/accounts/abi/bind/bind_test.go
@@ -399,7 +399,6 @@ var bindTests = []struct {
 			sim.Commit()
 
 			// Set the field with automatic estimation and check that it succeeds
-			auth.GasLimit = nil
 			if _, err := limiter.SetField(auth, "automatic"); err != nil {
 				t.Fatalf("Failed to call automatically gased transaction: %v", err)
 			}
diff --git a/accounts/abi/bind/util_test.go b/accounts/abi/bind/util_test.go
index d24aa721e..49e6dc813 100644
--- a/accounts/abi/bind/util_test.go
+++ b/accounts/abi/bind/util_test.go
@@ -34,18 +34,18 @@ var testKey, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d
 
 var waitDeployedTests = map[string]struct {
 	code        string
-	gas         *big.Int
+	gas         uint64
 	wantAddress common.Address
 	wantErr     error
 }{
 	"successful deploy": {
 		code:        `6060604052600a8060106000396000f360606040526008565b00`,
-		gas:         big.NewInt(3000000),
+		gas:         3000000,
 		wantAddress: common.HexToAddress("0x3a220f351252089d385b29beca14e27f204c296a"),
 	},
 	"empty code": {
 		code:        ``,
-		gas:         big.NewInt(300000),
+		gas:         300000,
 		wantErr:     bind.ErrNoCodeAfterDeploy,
 		wantAddress: common.HexToAddress("0x3a220f351252089d385b29beca14e27f204c296a"),
 	},
diff --git a/accounts/usbwallet/trezor.go b/accounts/usbwallet/trezor.go
index 159cb2ea9..b84a95599 100644
--- a/accounts/usbwallet/trezor.go
+++ b/accounts/usbwallet/trezor.go
@@ -180,7 +180,7 @@ func (w *trezorDriver) trezorSign(derivationPath []uint32, tx *types.Transaction
 		AddressN:   derivationPath,
 		Nonce:      new(big.Int).SetUint64(tx.Nonce()).Bytes(),
 		GasPrice:   tx.GasPrice().Bytes(),
-		GasLimit:   tx.Gas().Bytes(),
+		GasLimit:   new(big.Int).SetUint64(tx.Gas()).Bytes(),
 		Value:      tx.Value().Bytes(),
 		DataLength: &length,
 	}
diff --git a/cmd/faucet/faucet.go b/cmd/faucet/faucet.go
index 75ec124c1..051f9254c 100644
--- a/cmd/faucet/faucet.go
+++ b/cmd/faucet/faucet.go
@@ -473,7 +473,7 @@ func (f *faucet) apiHandler(conn *websocket.Conn) {
 			amount = new(big.Int).Mul(amount, new(big.Int).Exp(big.NewInt(5), big.NewInt(int64(msg.Tier)), nil))
 			amount = new(big.Int).Div(amount, new(big.Int).Exp(big.NewInt(2), big.NewInt(int64(msg.Tier)), nil))
 
-			tx := types.NewTransaction(f.nonce+uint64(len(f.reqs)), address, amount, big.NewInt(21000), f.price, nil)
+			tx := types.NewTransaction(f.nonce+uint64(len(f.reqs)), address, amount, 21000, f.price, nil)
 			signed, err := f.keystore.SignTx(f.account, tx, f.config.ChainId)
 			if err != nil {
 				f.lock.Unlock()
diff --git a/cmd/puppeth/genesis.go b/cmd/puppeth/genesis.go
index 5e36f7fce..f747f4739 100644
--- a/cmd/puppeth/genesis.go
+++ b/cmd/puppeth/genesis.go
@@ -44,7 +44,7 @@ type cppEthereumGenesisSpec struct {
 		MaximumExtraDataSize    hexutil.Uint64 `json:"maximumExtraDataSize"`
 		MinGasLimit             hexutil.Uint64 `json:"minGasLimit"`
 		MaxGasLimit             hexutil.Uint64 `json:"maxGasLimit"`
-		GasLimitBoundDivisor    *hexutil.Big   `json:"gasLimitBoundDivisor"`
+		GasLimitBoundDivisor    hexutil.Uint64 `json:"gasLimitBoundDivisor"`
 		MinimumDifficulty       *hexutil.Big   `json:"minimumDifficulty"`
 		DifficultyBoundDivisor  *hexutil.Big   `json:"difficultyBoundDivisor"`
 		DurationLimit           *hexutil.Big   `json:"durationLimit"`
@@ -107,11 +107,11 @@ func newCppEthereumGenesisSpec(network string, genesis *core.Genesis) (*cppEther
 	spec.Params.ChainID = (hexutil.Uint64)(genesis.Config.ChainId.Uint64())
 
 	spec.Params.MaximumExtraDataSize = (hexutil.Uint64)(params.MaximumExtraDataSize)
-	spec.Params.MinGasLimit = (hexutil.Uint64)(params.MinGasLimit.Uint64())
+	spec.Params.MinGasLimit = (hexutil.Uint64)(params.MinGasLimit)
 	spec.Params.MaxGasLimit = (hexutil.Uint64)(math.MaxUint64)
 	spec.Params.MinimumDifficulty = (*hexutil.Big)(params.MinimumDifficulty)
 	spec.Params.DifficultyBoundDivisor = (*hexutil.Big)(params.DifficultyBoundDivisor)
-	spec.Params.GasLimitBoundDivisor = (*hexutil.Big)(params.GasLimitBoundDivisor)
+	spec.Params.GasLimitBoundDivisor = (hexutil.Uint64)(params.GasLimitBoundDivisor)
 	spec.Params.DurationLimit = (*hexutil.Big)(params.DurationLimit)
 	spec.Params.BlockReward = (*hexutil.Big)(ethash.FrontierBlockReward)
 
@@ -168,26 +168,26 @@ type parityChainSpec struct {
 	Engine struct {
 		Ethash struct {
 			Params struct {
-				MinimumDifficulty      *hexutil.Big `json:"minimumDifficulty"`
-				DifficultyBoundDivisor *hexutil.Big `json:"difficultyBoundDivisor"`
-				GasLimitBoundDivisor   *hexutil.Big `json:"gasLimitBoundDivisor"`
-				DurationLimit          *hexutil.Big `json:"durationLimit"`
-				BlockReward            *hexutil.Big `json:"blockReward"`
-				HomesteadTransition    uint64       `json:"homesteadTransition"`
-				EIP150Transition       uint64       `json:"eip150Transition"`
-				EIP160Transition       uint64       `json:"eip160Transition"`
-				EIP161abcTransition    uint64       `json:"eip161abcTransition"`
-				EIP161dTransition      uint64       `json:"eip161dTransition"`
-				EIP649Reward           *hexutil.Big `json:"eip649Reward"`
-				EIP100bTransition      uint64       `json:"eip100bTransition"`
-				EIP649Transition       uint64       `json:"eip649Transition"`
+				MinimumDifficulty      *hexutil.Big   `json:"minimumDifficulty"`
+				DifficultyBoundDivisor *hexutil.Big   `json:"difficultyBoundDivisor"`
+				GasLimitBoundDivisor   hexutil.Uint64 `json:"gasLimitBoundDivisor"`
+				DurationLimit          *hexutil.Big   `json:"durationLimit"`
+				BlockReward            *hexutil.Big   `json:"blockReward"`
+				HomesteadTransition    uint64         `json:"homesteadTransition"`
+				EIP150Transition       uint64         `json:"eip150Transition"`
+				EIP160Transition       uint64         `json:"eip160Transition"`
+				EIP161abcTransition    uint64         `json:"eip161abcTransition"`
+				EIP161dTransition      uint64         `json:"eip161dTransition"`
+				EIP649Reward           *hexutil.Big   `json:"eip649Reward"`
+				EIP100bTransition      uint64         `json:"eip100bTransition"`
+				EIP649Transition       uint64         `json:"eip649Transition"`
 			} `json:"params"`
 		} `json:"Ethash"`
 	} `json:"engine"`
 
 	Params struct {
 		MaximumExtraDataSize hexutil.Uint64 `json:"maximumExtraDataSize"`
-		MinGasLimit          *hexutil.Big   `json:"minGasLimit"`
+		MinGasLimit          hexutil.Uint64 `json:"minGasLimit"`
 		NetworkID            hexutil.Uint64 `json:"networkID"`
 		MaxCodeSize          uint64         `json:"maxCodeSize"`
 		EIP155Transition     uint64         `json:"eip155Transition"`
@@ -270,7 +270,7 @@ func newParityChainSpec(network string, genesis *core.Genesis, bootnodes []strin
 	}
 	spec.Engine.Ethash.Params.MinimumDifficulty = (*hexutil.Big)(params.MinimumDifficulty)
 	spec.Engine.Ethash.Params.DifficultyBoundDivisor = (*hexutil.Big)(params.DifficultyBoundDivisor)
-	spec.Engine.Ethash.Params.GasLimitBoundDivisor = (*hexutil.Big)(params.GasLimitBoundDivisor)
+	spec.Engine.Ethash.Params.GasLimitBoundDivisor = (hexutil.Uint64)(params.GasLimitBoundDivisor)
 	spec.Engine.Ethash.Params.DurationLimit = (*hexutil.Big)(params.DurationLimit)
 	spec.Engine.Ethash.Params.BlockReward = (*hexutil.Big)(ethash.FrontierBlockReward)
 	spec.Engine.Ethash.Params.HomesteadTransition = genesis.Config.HomesteadBlock.Uint64()
@@ -283,7 +283,7 @@ func newParityChainSpec(network string, genesis *core.Genesis, bootnodes []strin
 	spec.Engine.Ethash.Params.EIP649Transition = genesis.Config.ByzantiumBlock.Uint64()
 
 	spec.Params.MaximumExtraDataSize = (hexutil.Uint64)(params.MaximumExtraDataSize)
-	spec.Params.MinGasLimit = (*hexutil.Big)(params.MinGasLimit)
+	spec.Params.MinGasLimit = (hexutil.Uint64)(params.MinGasLimit)
 	spec.Params.NetworkID = (hexutil.Uint64)(genesis.Config.ChainId.Uint64())
 	spec.Params.MaxCodeSize = params.MaxCodeSize
 	spec.Params.EIP155Transition = genesis.Config.EIP155Block.Uint64()
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index 30edf199c..734cf6f36 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -313,7 +313,7 @@ var (
 	TargetGasLimitFlag = cli.Uint64Flag{
 		Name:  "targetgaslimit",
 		Usage: "Target gas limit sets the artificial target gas floor for the blocks to mine",
-		Value: params.GenesisGasLimit.Uint64(),
+		Value: params.GenesisGasLimit,
 	}
 	EtherbaseFlag = cli.StringFlag{
 		Name:  "etherbase",
@@ -1138,7 +1138,7 @@ func RegisterEthStatsService(stack *node.Node, url string) {
 // SetupNetwork configures the system for either the main net or some test network.
 func SetupNetwork(ctx *cli.Context) {
 	// TODO(fjl): move target gas limit into config
-	params.TargetGasLimit = new(big.Int).SetUint64(ctx.GlobalUint64(TargetGasLimitFlag.Name))
+	params.TargetGasLimit = ctx.GlobalUint64(TargetGasLimitFlag.Name)
 }
 
 // MakeChainDatabase open an LevelDB using the flags passed to the client and will hard crash if it fails.
diff --git a/consensus/ethash/algorithm_test.go b/consensus/ethash/algorithm_test.go
index 7765ff9fe..a54f3b582 100644
--- a/consensus/ethash/algorithm_test.go
+++ b/consensus/ethash/algorithm_test.go
@@ -688,8 +688,8 @@ func TestConcurrentDiskCacheGeneration(t *testing.T) {
 		TxHash:      common.HexToHash("0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"),
 		ReceiptHash: common.HexToHash("0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"),
 		Difficulty:  big.NewInt(167925187834220),
-		GasLimit:    big.NewInt(4015682),
-		GasUsed:     big.NewInt(0),
+		GasLimit:    4015682,
+		GasUsed:     0,
 		Time:        big.NewInt(1488928920),
 		Extra:       []byte("www.bw.com"),
 		MixDigest:   common.HexToHash("0x3e140b0784516af5e5ec6730f2fb20cca22f32be399b9e4ad77d32541f798cd0"),
diff --git a/consensus/ethash/consensus.go b/consensus/ethash/consensus.go
index 0a2f1520e..0af68c31a 100644
--- a/consensus/ethash/consensus.go
+++ b/consensus/ethash/consensus.go
@@ -246,24 +246,24 @@ func (ethash *Ethash) verifyHeader(chain consensus.ChainReader, header, parent *
 		return fmt.Errorf("invalid difficulty: have %v, want %v", header.Difficulty, expected)
 	}
 	// Verify that the gas limit is <= 2^63-1
-	if header.GasLimit.Cmp(math.MaxBig63) > 0 {
-		return fmt.Errorf("invalid gasLimit: have %v, max %v", header.GasLimit, math.MaxBig63)
+	cap := uint64(0x7fffffffffffffff)
+	if header.GasLimit > cap {
+		return fmt.Errorf("invalid gasLimit: have %v, max %v", header.GasLimit, cap)
 	}
 	// Verify that the gasUsed is <= gasLimit
-	if header.GasUsed.Cmp(header.GasLimit) > 0 {
-		return fmt.Errorf("invalid gasUsed: have %v, gasLimit %v", header.GasUsed, header.GasLimit)
+	if header.GasUsed > header.GasLimit {
+		return fmt.Errorf("invalid gasUsed: have %d, gasLimit %d", header.GasUsed, header.GasLimit)
 	}
 
 	// Verify that the gas limit remains within allowed bounds
-	diff := new(big.Int).Set(parent.GasLimit)
-	diff = diff.Sub(diff, header.GasLimit)
-	diff.Abs(diff)
-
-	limit := new(big.Int).Set(parent.GasLimit)
-	limit = limit.Div(limit, params.GasLimitBoundDivisor)
+	diff := int64(parent.GasLimit) - int64(header.GasLimit)
+	if diff < 0 {
+		diff *= -1
+	}
+	limit := parent.GasLimit / params.GasLimitBoundDivisor
 
-	if diff.Cmp(limit) >= 0 || header.GasLimit.Cmp(params.MinGasLimit) < 0 {
-		return fmt.Errorf("invalid gas limit: have %v, want %v += %v", header.GasLimit, parent.GasLimit, limit)
+	if uint64(diff) >= limit || header.GasLimit < params.MinGasLimit {
+		return fmt.Errorf("invalid gas limit: have %d, want %d += %d", header.GasLimit, parent.GasLimit, limit)
 	}
 	// Verify that the block number is parent's +1
 	if diff := new(big.Int).Sub(header.Number, parent.Number); diff.Cmp(big.NewInt(1)) != 0 {
diff --git a/contracts/chequebook/cheque.go b/contracts/chequebook/cheque.go
index 09daa9248..f6335adc6 100644
--- a/contracts/chequebook/cheque.go
+++ b/contracts/chequebook/cheque.go
@@ -56,8 +56,8 @@ import (
 // * watching incoming ether
 
 var (
-	gasToCash = big.NewInt(2000000) // gas cost of a cash transaction using chequebook
-	// gasToDeploy = big.NewInt(3000000)
+	gasToCash = uint64(2000000) // gas cost of a cash transaction using chequebook
+	// gasToDeploy = uint64(3000000)
 )
 
 // Backend wraps all methods required for chequebook operation.
diff --git a/contracts/ens/ens.go b/contracts/ens/ens.go
index c292a1714..60c3c83ab 100644
--- a/contracts/ens/ens.go
+++ b/contracts/ens/ens.go
@@ -19,7 +19,6 @@ package ens
 //go:generate abigen --sol contract/ens.sol --pkg contract --out contract/ens.go
 
 import (
-	"math/big"
 	"strings"
 
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
@@ -163,7 +162,7 @@ func (self *ENS) Register(name string) (*types.Transaction, error) {
 	}
 
 	opts := self.TransactOpts
-	opts.GasLimit = big.NewInt(200000)
+	opts.GasLimit = 200000
 	return registrar.Contract.Register(&opts, label, self.TransactOpts.From)
 }
 
@@ -178,6 +177,6 @@ func (self *ENS) SetContentHash(name string, hash common.Hash) (*types.Transacti
 	}
 
 	opts := self.TransactOpts
-	opts.GasLimit = big.NewInt(200000)
+	opts.GasLimit = 200000
 	return resolver.Contract.SetContent(&opts, node, hash)
 }
diff --git a/contracts/ens/ens_test.go b/contracts/ens/ens_test.go
index 5faa9b1ad..9ab137581 100644
--- a/contracts/ens/ens_test.go
+++ b/contracts/ens/ens_test.go
@@ -37,7 +37,7 @@ func TestENS(t *testing.T) {
 	contractBackend := backends.NewSimulatedBackend(core.GenesisAlloc{addr: {Balance: big.NewInt(1000000000)}})
 	transactOpts := bind.NewKeyedTransactor(key)
 	// Workaround for bug estimating gas in the call to Register
-	transactOpts.GasLimit = big.NewInt(1000000)
+	transactOpts.GasLimit = 1000000
 
 	ens, err := DeployENS(transactOpts, contractBackend)
 	if err != nil {
diff --git a/core/bench_test.go b/core/bench_test.go
index 9c7cd81c4..f976331d1 100644
--- a/core/bench_test.go
+++ b/core/bench_test.go
@@ -84,7 +84,7 @@ func genValueTx(nbytes int) func(int, *BlockGen) {
 	return func(i int, gen *BlockGen) {
 		toaddr := common.Address{}
 		data := make([]byte, nbytes)
-		gas := IntrinsicGas(data, false, false)
+		gas, _ := IntrinsicGas(data, false, false)
 		tx, _ := types.SignTx(types.NewTransaction(gen.TxNonce(benchRootAddr), toaddr, big.NewInt(1), gas, nil, data), types.HomesteadSigner{}, benchRootKey)
 		gen.AddTx(tx)
 	}
@@ -93,7 +93,6 @@ func genValueTx(nbytes int) func(int, *BlockGen) {
 var (
 	ringKeys  = make([]*ecdsa.PrivateKey, 1000)
 	ringAddrs = make([]common.Address, len(ringKeys))
-	bigTxGas  = new(big.Int).SetUint64(params.TxGas)
 )
 
 func init() {
@@ -113,8 +112,8 @@ func genTxRing(naccounts int) func(int, *BlockGen) {
 	return func(i int, gen *BlockGen) {
 		gas := CalcGasLimit(gen.PrevBlock(i - 1))
 		for {
-			gas.Sub(gas, bigTxGas)
-			if gas.Cmp(bigTxGas) < 0 {
+			gas -= params.TxGas
+			if gas < params.TxGas {
 				break
 			}
 			to := (from + 1) % naccounts
@@ -122,7 +121,7 @@ func genTxRing(naccounts int) func(int, *BlockGen) {
 				gen.TxNonce(ringAddrs[from]),
 				ringAddrs[to],
 				benchRootFunds,
-				bigTxGas,
+				params.TxGas,
 				nil,
 				nil,
 			)
diff --git a/core/block_validator.go b/core/block_validator.go
index e9cfd0482..143728bb8 100644
--- a/core/block_validator.go
+++ b/core/block_validator.go
@@ -18,9 +18,7 @@ package core
 
 import (
 	"fmt"
-	"math/big"
 
-	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -76,10 +74,10 @@ func (v *BlockValidator) ValidateBody(block *types.Block) error {
 // transition, such as amount of used gas, the receipt roots and the state root
 // itself. ValidateState returns a database batch if the validation was a success
 // otherwise nil and an error is returned.
-func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *state.StateDB, receipts types.Receipts, usedGas *big.Int) error {
+func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *state.StateDB, receipts types.Receipts, usedGas uint64) error {
 	header := block.Header()
-	if block.GasUsed().Cmp(usedGas) != 0 {
-		return fmt.Errorf("invalid gas used (remote: %v local: %v)", block.GasUsed(), usedGas)
+	if block.GasUsed() != usedGas {
+		return fmt.Errorf("invalid gas used (remote: %d local: %d)", block.GasUsed(), usedGas)
 	}
 	// Validate the received block's bloom with the one derived from the generated receipts.
 	// For valid blocks this should always validate to true.
@@ -101,17 +99,13 @@ func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *stat
 }
 
 // CalcGasLimit computes the gas limit of the next block after parent.
-// The result may be modified by the caller.
 // This is miner strategy, not consensus protocol.
-func CalcGasLimit(parent *types.Block) *big.Int {
+func CalcGasLimit(parent *types.Block) uint64 {
 	// contrib = (parentGasUsed * 3 / 2) / 1024
-	contrib := new(big.Int).Mul(parent.GasUsed(), big.NewInt(3))
-	contrib = contrib.Div(contrib, big.NewInt(2))
-	contrib = contrib.Div(contrib, params.GasLimitBoundDivisor)
+	contrib := (parent.GasUsed() + parent.GasUsed()/2) / params.GasLimitBoundDivisor
 
 	// decay = parentGasLimit / 1024 -1
-	decay := new(big.Int).Div(parent.GasLimit(), params.GasLimitBoundDivisor)
-	decay.Sub(decay, big.NewInt(1))
+	decay := parent.GasLimit()/params.GasLimitBoundDivisor - 1
 
 	/*
 		strategy: gasLimit of block-to-mine is set based on parent's
@@ -120,15 +114,17 @@ func CalcGasLimit(parent *types.Block) *big.Int {
 		at that usage) the amount increased/decreased depends on how far away
 		from parentGasLimit * (2/3) parentGasUsed is.
 	*/
-	gl := new(big.Int).Sub(parent.GasLimit(), decay)
-	gl = gl.Add(gl, contrib)
-	gl.Set(math.BigMax(gl, params.MinGasLimit))
-
+	limit := parent.GasLimit() - decay + contrib
+	if limit < params.MinGasLimit {
+		limit = params.MinGasLimit
+	}
 	// however, if we're now below the target (TargetGasLimit) we increase the
 	// limit as much as we can (parentGasLimit / 1024 -1)
-	if gl.Cmp(params.TargetGasLimit) < 0 {
-		gl.Add(parent.GasLimit(), decay)
-		gl.Set(math.BigMin(gl, params.TargetGasLimit))
+	if limit < params.TargetGasLimit {
+		limit = parent.GasLimit() + decay
+		if limit > params.TargetGasLimit {
+			limit = params.TargetGasLimit
+		}
 	}
-	return gl
+	return limit
 }
diff --git a/core/blockchain.go b/core/blockchain.go
index 812f9e562..737fbe3ee 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -305,7 +305,7 @@ func (bc *BlockChain) FastSyncCommitHead(hash common.Hash) error {
 }
 
 // GasLimit returns the gas limit of the current HEAD block.
-func (bc *BlockChain) GasLimit() *big.Int {
+func (bc *BlockChain) GasLimit() uint64 {
 	bc.mu.RLock()
 	defer bc.mu.RUnlock()
 
@@ -677,9 +677,9 @@ func SetReceiptsData(config *params.ChainConfig, block *types.Block, receipts ty
 		}
 		// The used gas can be calculated based on previous receipts
 		if j == 0 {
-			receipts[j].GasUsed = new(big.Int).Set(receipts[j].CumulativeGasUsed)
+			receipts[j].GasUsed = receipts[j].CumulativeGasUsed
 		} else {
-			receipts[j].GasUsed = new(big.Int).Sub(receipts[j].CumulativeGasUsed, receipts[j-1].CumulativeGasUsed)
+			receipts[j].GasUsed = receipts[j].CumulativeGasUsed - receipts[j-1].CumulativeGasUsed
 		}
 		// The derived log fields can simply be set from the block and transaction
 		for k := 0; k < len(receipts[j].Logs); k++ {
@@ -1002,7 +1002,7 @@ func (bc *BlockChain) insertChain(chain types.Blocks) (int, []interface{}, []*ty
 			events = append(events, ChainSideEvent{block})
 		}
 		stats.processed++
-		stats.usedGas += usedGas.Uint64()
+		stats.usedGas += usedGas
 		stats.report(chain, i)
 	}
 	// Append a single chain head event if we've progressed the chain
diff --git a/core/blockchain_test.go b/core/blockchain_test.go
index cb2e47104..26c816027 100644
--- a/core/blockchain_test.go
+++ b/core/blockchain_test.go
@@ -340,11 +340,11 @@ func testBrokenChain(t *testing.T, full bool) {
 type bproc struct{}
 
 func (bproc) ValidateBody(*types.Block) error { return nil }
-func (bproc) ValidateState(block, parent *types.Block, state *state.StateDB, receipts types.Receipts, usedGas *big.Int) error {
+func (bproc) ValidateState(block, parent *types.Block, state *state.StateDB, receipts types.Receipts, usedGas uint64) error {
 	return nil
 }
-func (bproc) Process(block *types.Block, statedb *state.StateDB, cfg vm.Config) (types.Receipts, []*types.Log, *big.Int, error) {
-	return nil, nil, new(big.Int), nil
+func (bproc) Process(block *types.Block, statedb *state.StateDB, cfg vm.Config) (types.Receipts, []*types.Log, uint64, error) {
+	return nil, nil, 0, nil
 }
 
 func makeHeaderChainWithDiff(genesis *types.Block, d []int, seed byte) []*types.Header {
@@ -506,8 +506,8 @@ func testReorgBadHashes(t *testing.T, full bool) {
 		if ncm.CurrentBlock().Hash() != blocks[2].Header().Hash() {
 			t.Errorf("last block hash mismatch: have: %x, want %x", ncm.CurrentBlock().Hash(), blocks[2].Header().Hash())
 		}
-		if blocks[2].Header().GasLimit.Cmp(ncm.GasLimit()) != 0 {
-			t.Errorf("last  block gasLimit mismatch: have: %x, want %x", ncm.GasLimit(), blocks[2].Header().GasLimit)
+		if blocks[2].Header().GasLimit != ncm.GasLimit() {
+			t.Errorf("last  block gasLimit mismatch: have: %d, want %d", ncm.GasLimit(), blocks[2].Header().GasLimit)
 		}
 	} else {
 		if ncm.CurrentHeader().Hash() != headers[2].Hash() {
@@ -594,7 +594,7 @@ func TestFastVsFullChains(t *testing.T) {
 		// If the block number is multiple of 3, send a few bonus transactions to the miner
 		if i%3 == 2 {
 			for j := 0; j < i%4+1; j++ {
-				tx, err := types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{0x00}, big.NewInt(1000), bigTxGas, nil, nil), signer, key)
+				tx, err := types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{0x00}, big.NewInt(1000), params.TxGas, nil, nil), signer, key)
 				if err != nil {
 					panic(err)
 				}
@@ -767,8 +767,8 @@ func TestChainTxReorgs(t *testing.T) {
 	// Create two transactions shared between the chains:
 	//  - postponed: transaction included at a later block in the forked chain
 	//  - swapped: transaction included at the same block number in the forked chain
-	postponed, _ := types.SignTx(types.NewTransaction(0, addr1, big.NewInt(1000), bigTxGas, nil, nil), signer, key1)
-	swapped, _ := types.SignTx(types.NewTransaction(1, addr1, big.NewInt(1000), bigTxGas, nil, nil), signer, key1)
+	postponed, _ := types.SignTx(types.NewTransaction(0, addr1, big.NewInt(1000), params.TxGas, nil, nil), signer, key1)
+	swapped, _ := types.SignTx(types.NewTransaction(1, addr1, big.NewInt(1000), params.TxGas, nil, nil), signer, key1)
 
 	// Create two transactions that will be dropped by the forked chain:
 	//  - pastDrop: transaction dropped retroactively from a past block
@@ -784,13 +784,13 @@ func TestChainTxReorgs(t *testing.T) {
 	chain, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 3, func(i int, gen *BlockGen) {
 		switch i {
 		case 0:
-			pastDrop, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr2, big.NewInt(1000), bigTxGas, nil, nil), signer, key2)
+			pastDrop, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr2, big.NewInt(1000), params.TxGas, nil, nil), signer, key2)
 
 			gen.AddTx(pastDrop)  // This transaction will be dropped in the fork from below the split point
 			gen.AddTx(postponed) // This transaction will be postponed till block #3 in the fork
 
 		case 2:
-			freshDrop, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr2, big.NewInt(1000), bigTxGas, nil, nil), signer, key2)
+			freshDrop, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr2, big.NewInt(1000), params.TxGas, nil, nil), signer, key2)
 
 			gen.AddTx(freshDrop) // This transaction will be dropped in the fork from exactly at the split point
 			gen.AddTx(swapped)   // This transaction will be swapped out at the exact height
@@ -809,18 +809,18 @@ func TestChainTxReorgs(t *testing.T) {
 	chain, _ = GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 5, func(i int, gen *BlockGen) {
 		switch i {
 		case 0:
-			pastAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), bigTxGas, nil, nil), signer, key3)
+			pastAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), params.TxGas, nil, nil), signer, key3)
 			gen.AddTx(pastAdd) // This transaction needs to be injected during reorg
 
 		case 2:
 			gen.AddTx(postponed) // This transaction was postponed from block #1 in the original chain
 			gen.AddTx(swapped)   // This transaction was swapped from the exact current spot in the original chain
 
-			freshAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), bigTxGas, nil, nil), signer, key3)
+			freshAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), params.TxGas, nil, nil), signer, key3)
 			gen.AddTx(freshAdd) // This transaction will be added exactly at reorg time
 
 		case 3:
-			futureAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), bigTxGas, nil, nil), signer, key3)
+			futureAdd, _ = types.SignTx(types.NewTransaction(gen.TxNonce(addr3), addr3, big.NewInt(1000), params.TxGas, nil, nil), signer, key3)
 			gen.AddTx(futureAdd) // This transaction will be added after a full reorg
 		}
 	})
@@ -877,7 +877,7 @@ func TestLogReorgs(t *testing.T) {
 	blockchain.SubscribeRemovedLogsEvent(rmLogsCh)
 	chain, _ := GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), db, 2, func(i int, gen *BlockGen) {
 		if i == 1 {
-			tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), big.NewInt(1000000), new(big.Int), code), signer, key1)
+			tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), 1000000, new(big.Int), code), signer, key1)
 			if err != nil {
 				t.Fatalf("failed to create tx: %v", err)
 			}
@@ -926,7 +926,7 @@ func TestReorgSideEvent(t *testing.T) {
 	}
 
 	replacementBlocks, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 4, func(i int, gen *BlockGen) {
-		tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), big.NewInt(1000000), new(big.Int), nil), signer, key1)
+		tx, err := types.SignTx(types.NewContractCreation(gen.TxNonce(addr1), new(big.Int), 1000000, new(big.Int), nil), signer, key1)
 		if i == 2 {
 			gen.OffsetTime(-9)
 		}
@@ -1051,7 +1051,7 @@ func TestEIP155Transition(t *testing.T) {
 			tx      *types.Transaction
 			err     error
 			basicTx = func(signer types.Signer) (*types.Transaction, error) {
-				return types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{}, new(big.Int), big.NewInt(21000), new(big.Int), nil), signer, key)
+				return types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{}, new(big.Int), 21000, new(big.Int), nil), signer, key)
 			}
 		)
 		switch i {
@@ -1114,7 +1114,7 @@ func TestEIP155Transition(t *testing.T) {
 			tx      *types.Transaction
 			err     error
 			basicTx = func(signer types.Signer) (*types.Transaction, error) {
-				return types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{}, new(big.Int), big.NewInt(21000), new(big.Int), nil), signer, key)
+				return types.SignTx(types.NewTransaction(block.TxNonce(address), common.Address{}, new(big.Int), 21000, new(big.Int), nil), signer, key)
 			}
 		)
 		switch i {
@@ -1162,11 +1162,11 @@ func TestEIP161AccountRemoval(t *testing.T) {
 		)
 		switch i {
 		case 0:
-			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), big.NewInt(21000), new(big.Int), nil), signer, key)
+			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), 21000, new(big.Int), nil), signer, key)
 		case 1:
-			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), big.NewInt(21000), new(big.Int), nil), signer, key)
+			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), 21000, new(big.Int), nil), signer, key)
 		case 2:
-			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), big.NewInt(21000), new(big.Int), nil), signer, key)
+			tx, err = types.SignTx(types.NewTransaction(block.TxNonce(address), theAddr, new(big.Int), 21000, new(big.Int), nil), signer, key)
 		}
 		if err != nil {
 			t.Fatal(err)
diff --git a/core/chain_makers.go b/core/chain_makers.go
index 0e5e3791e..5e264a994 100644
--- a/core/chain_makers.go
+++ b/core/chain_makers.go
@@ -86,7 +86,7 @@ func (b *BlockGen) AddTx(tx *types.Transaction) {
 		b.SetCoinbase(common.Address{})
 	}
 	b.statedb.Prepare(tx.Hash(), common.Hash{}, len(b.txs))
-	receipt, _, err := ApplyTransaction(b.config, nil, &b.header.Coinbase, b.gasPool, b.statedb, b.header, tx, b.header.GasUsed, vm.Config{})
+	receipt, _, err := ApplyTransaction(b.config, nil, &b.header.Coinbase, b.gasPool, b.statedb, b.header, tx, &b.header.GasUsed, vm.Config{})
 	if err != nil {
 		panic(err)
 	}
@@ -232,7 +232,6 @@ func makeHeader(chain consensus.ChainReader, parent *types.Block, state *state.S
 			UncleHash:  parent.UncleHash(),
 		}),
 		GasLimit: CalcGasLimit(parent),
-		GasUsed:  new(big.Int),
 		Number:   new(big.Int).Add(parent.Number(), common.Big1),
 		Time:     time,
 	}
diff --git a/core/chain_makers_test.go b/core/chain_makers_test.go
index 011efe342..a3b80da29 100644
--- a/core/chain_makers_test.go
+++ b/core/chain_makers_test.go
@@ -54,13 +54,13 @@ func ExampleGenerateChain() {
 		switch i {
 		case 0:
 			// In block 1, addr1 sends addr2 some ether.
-			tx, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(10000), bigTxGas, nil, nil), signer, key1)
+			tx, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(10000), params.TxGas, nil, nil), signer, key1)
 			gen.AddTx(tx)
 		case 1:
 			// In block 2, addr1 sends some more ether to addr2.
 			// addr2 passes it on to addr3.
-			tx1, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(1000), bigTxGas, nil, nil), signer, key1)
-			tx2, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr3, big.NewInt(1000), bigTxGas, nil, nil), signer, key2)
+			tx1, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(1000), params.TxGas, nil, nil), signer, key1)
+			tx2, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr3, big.NewInt(1000), params.TxGas, nil, nil), signer, key2)
 			gen.AddTx(tx1)
 			gen.AddTx(tx2)
 		case 2:
diff --git a/core/database_util_test.go b/core/database_util_test.go
index 36f43cf50..ab4e45a47 100644
--- a/core/database_util_test.go
+++ b/core/database_util_test.go
@@ -290,9 +290,9 @@ func TestHeadStorage(t *testing.T) {
 func TestLookupStorage(t *testing.T) {
 	db, _ := ethdb.NewMemDatabase()
 
-	tx1 := types.NewTransaction(1, common.BytesToAddress([]byte{0x11}), big.NewInt(111), big.NewInt(1111), big.NewInt(11111), []byte{0x11, 0x11, 0x11})
-	tx2 := types.NewTransaction(2, common.BytesToAddress([]byte{0x22}), big.NewInt(222), big.NewInt(2222), big.NewInt(22222), []byte{0x22, 0x22, 0x22})
-	tx3 := types.NewTransaction(3, common.BytesToAddress([]byte{0x33}), big.NewInt(333), big.NewInt(3333), big.NewInt(33333), []byte{0x33, 0x33, 0x33})
+	tx1 := types.NewTransaction(1, common.BytesToAddress([]byte{0x11}), big.NewInt(111), 1111, big.NewInt(11111), []byte{0x11, 0x11, 0x11})
+	tx2 := types.NewTransaction(2, common.BytesToAddress([]byte{0x22}), big.NewInt(222), 2222, big.NewInt(22222), []byte{0x22, 0x22, 0x22})
+	tx3 := types.NewTransaction(3, common.BytesToAddress([]byte{0x33}), big.NewInt(333), 3333, big.NewInt(33333), []byte{0x33, 0x33, 0x33})
 	txs := []*types.Transaction{tx1, tx2, tx3}
 
 	block := types.NewBlock(&types.Header{Number: big.NewInt(314)}, txs, nil, nil)
@@ -337,25 +337,25 @@ func TestBlockReceiptStorage(t *testing.T) {
 
 	receipt1 := &types.Receipt{
 		Status:            types.ReceiptStatusFailed,
-		CumulativeGasUsed: big.NewInt(1),
+		CumulativeGasUsed: 1,
 		Logs: []*types.Log{
 			{Address: common.BytesToAddress([]byte{0x11})},
 			{Address: common.BytesToAddress([]byte{0x01, 0x11})},
 		},
 		TxHash:          common.BytesToHash([]byte{0x11, 0x11}),
 		ContractAddress: common.BytesToAddress([]byte{0x01, 0x11, 0x11}),
-		GasUsed:         big.NewInt(111111),
+		GasUsed:         111111,
 	}
 	receipt2 := &types.Receipt{
 		PostState:         common.Hash{2}.Bytes(),
-		CumulativeGasUsed: big.NewInt(2),
+		CumulativeGasUsed: 2,
 		Logs: []*types.Log{
 			{Address: common.BytesToAddress([]byte{0x22})},
 			{Address: common.BytesToAddress([]byte{0x02, 0x22})},
 		},
 		TxHash:          common.BytesToHash([]byte{0x22, 0x22}),
 		ContractAddress: common.BytesToAddress([]byte{0x02, 0x22, 0x22}),
-		GasUsed:         big.NewInt(222222),
+		GasUsed:         222222,
 	}
 	receipts := []*types.Receipt{receipt1, receipt2}
 
diff --git a/core/evm.go b/core/evm.go
index 4912aa650..55db53927 100644
--- a/core/evm.go
+++ b/core/evm.go
@@ -53,7 +53,7 @@ func NewEVMContext(msg Message, header *types.Header, chain ChainContext, author
 		BlockNumber: new(big.Int).Set(header.Number),
 		Time:        new(big.Int).Set(header.Time),
 		Difficulty:  new(big.Int).Set(header.Difficulty),
-		GasLimit:    new(big.Int).Set(header.GasLimit),
+		GasLimit:    header.GasLimit,
 		GasPrice:    new(big.Int).Set(msg.GasPrice()),
 	}
 }
diff --git a/core/gaspool.go b/core/gaspool.go
index ef99908cf..c3ee5c198 100644
--- a/core/gaspool.go
+++ b/core/gaspool.go
@@ -16,31 +16,34 @@
 
 package core
 
-import "math/big"
+import (
+	"fmt"
+	"math"
+)
 
-// GasPool tracks the amount of gas available during
-// execution of the transactions in a block.
-// The zero value is a pool with zero gas available.
-type GasPool big.Int
+// GasPool tracks the amount of gas available during execution of the transactions
+// in a block. The zero value is a pool with zero gas available.
+type GasPool uint64
 
 // AddGas makes gas available for execution.
-func (gp *GasPool) AddGas(amount *big.Int) *GasPool {
-	i := (*big.Int)(gp)
-	i.Add(i, amount)
+func (gp *GasPool) AddGas(amount uint64) *GasPool {
+	if uint64(*gp) > math.MaxUint64-amount {
+		panic("gas pool pushed above uint64")
+	}
+	*(*uint64)(gp) += amount
 	return gp
 }
 
 // SubGas deducts the given amount from the pool if enough gas is
 // available and returns an error otherwise.
-func (gp *GasPool) SubGas(amount *big.Int) error {
-	i := (*big.Int)(gp)
-	if i.Cmp(amount) < 0 {
+func (gp *GasPool) SubGas(amount uint64) error {
+	if uint64(*gp) < amount {
 		return ErrGasLimitReached
 	}
-	i.Sub(i, amount)
+	*(*uint64)(gp) -= amount
 	return nil
 }
 
 func (gp *GasPool) String() string {
-	return (*big.Int)(gp).String()
+	return fmt.Sprintf("%d", *gp)
 }
diff --git a/core/gen_genesis.go b/core/gen_genesis.go
index 4d75704a6..6f941e35a 100644
--- a/core/gen_genesis.go
+++ b/core/gen_genesis.go
@@ -13,6 +13,8 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 )
 
+var _ = (*genesisSpecMarshaling)(nil)
+
 func (g Genesis) MarshalJSON() ([]byte, error) {
 	type Genesis struct {
 		Config     *params.ChainConfig                         `json:"config"`
diff --git a/core/genesis.go b/core/genesis.go
index df491ce0f..e22985b80 100644
--- a/core/genesis.go
+++ b/core/genesis.go
@@ -239,8 +239,8 @@ func (g *Genesis) ToBlock() (*types.Block, *state.StateDB) {
 		Time:       new(big.Int).SetUint64(g.Timestamp),
 		ParentHash: g.ParentHash,
 		Extra:      g.ExtraData,
-		GasLimit:   new(big.Int).SetUint64(g.GasLimit),
-		GasUsed:    new(big.Int).SetUint64(g.GasUsed),
+		GasLimit:   g.GasLimit,
+		GasUsed:    g.GasUsed,
 		Difficulty: g.Difficulty,
 		MixDigest:  g.Mixhash,
 		Coinbase:   g.Coinbase,
diff --git a/core/state/journal.go b/core/state/journal.go
index ddc819fe5..a89bb3d13 100644
--- a/core/state/journal.go
+++ b/core/state/journal.go
@@ -62,7 +62,7 @@ type (
 
 	// Changes to other state values.
 	refundChange struct {
-		prev *big.Int
+		prev uint64
 	}
 	addLogChange struct {
 		txhash common.Hash
diff --git a/core/state/statedb.go b/core/state/statedb.go
index de9fb367d..8e29104d5 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -57,7 +57,7 @@ type StateDB struct {
 	dbErr error
 
 	// The refund counter, also used by state transitioning.
-	refund *big.Int
+	refund uint64
 
 	thash, bhash common.Hash
 	txIndex      int
@@ -86,7 +86,6 @@ func New(root common.Hash, db Database) (*StateDB, error) {
 		trie:              tr,
 		stateObjects:      make(map[common.Address]*stateObject),
 		stateObjectsDirty: make(map[common.Address]struct{}),
-		refund:            new(big.Int),
 		logs:              make(map[common.Hash][]*types.Log),
 		preimages:         make(map[common.Hash][]byte),
 	}, nil
@@ -161,9 +160,9 @@ func (self *StateDB) Preimages() map[common.Hash][]byte {
 	return self.preimages
 }
 
-func (self *StateDB) AddRefund(gas *big.Int) {
-	self.journal = append(self.journal, refundChange{prev: new(big.Int).Set(self.refund)})
-	self.refund.Add(self.refund, gas)
+func (self *StateDB) AddRefund(gas uint64) {
+	self.journal = append(self.journal, refundChange{prev: self.refund})
+	self.refund += gas
 }
 
 // Exist reports whether the given account address exists in the state.
@@ -456,7 +455,7 @@ func (self *StateDB) Copy() *StateDB {
 		trie:              self.db.CopyTrie(self.trie),
 		stateObjects:      make(map[common.Address]*stateObject, len(self.stateObjectsDirty)),
 		stateObjectsDirty: make(map[common.Address]struct{}, len(self.stateObjectsDirty)),
-		refund:            new(big.Int).Set(self.refund),
+		refund:            self.refund,
 		logs:              make(map[common.Hash][]*types.Log, len(self.logs)),
 		logSize:           self.logSize,
 		preimages:         make(map[common.Hash][]byte),
@@ -506,9 +505,7 @@ func (self *StateDB) RevertToSnapshot(revid int) {
 }
 
 // GetRefund returns the current value of the refund counter.
-// The return value must not be modified by the caller and will become
-// invalid at the next call to AddRefund.
-func (self *StateDB) GetRefund() *big.Int {
+func (self *StateDB) GetRefund() uint64 {
 	return self.refund
 }
 
@@ -568,7 +565,7 @@ func (s *StateDB) DeleteSuicides() {
 func (s *StateDB) clearJournalAndRefund() {
 	s.journal = nil
 	s.validRevisions = s.validRevisions[:0]
-	s.refund = new(big.Int)
+	s.refund = 0
 }
 
 // CommitTo writes the state to the given database.
diff --git a/core/state/statedb_test.go b/core/state/statedb_test.go
index e9944cd74..5c80e3aa5 100644
--- a/core/state/statedb_test.go
+++ b/core/state/statedb_test.go
@@ -263,7 +263,7 @@ func newTestAction(addr common.Address, r *rand.Rand) testAction {
 		{
 			name: "AddRefund",
 			fn: func(a testAction, s *StateDB) {
-				s.AddRefund(big.NewInt(a.args[0]))
+				s.AddRefund(uint64(a.args[0]))
 			},
 			args:   make([]int64, 1),
 			noAddr: true,
@@ -396,7 +396,7 @@ func (test *snapshotTest) checkEqual(state, checkstate *StateDB) error {
 		}
 	}
 
-	if state.GetRefund().Cmp(checkstate.GetRefund()) != 0 {
+	if state.GetRefund() != checkstate.GetRefund() {
 		return fmt.Errorf("got GetRefund() == %d, want GetRefund() == %d",
 			state.GetRefund(), checkstate.GetRefund())
 	}
diff --git a/core/state_processor.go b/core/state_processor.go
index 689c83785..4dc58b9de 100644
--- a/core/state_processor.go
+++ b/core/state_processor.go
@@ -17,8 +17,6 @@
 package core
 
 import (
-	"math/big"
-
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/consensus/misc"
@@ -55,13 +53,13 @@ func NewStateProcessor(config *params.ChainConfig, bc *BlockChain, engine consen
 // Process returns the receipts and logs accumulated during the process and
 // returns the amount of gas that was used in the process. If any of the
 // transactions failed to execute due to insufficient gas it will return an error.
-func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg vm.Config) (types.Receipts, []*types.Log, *big.Int, error) {
+func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg vm.Config) (types.Receipts, []*types.Log, uint64, error) {
 	var (
-		receipts     types.Receipts
-		totalUsedGas = big.NewInt(0)
-		header       = block.Header()
-		allLogs      []*types.Log
-		gp           = new(GasPool).AddGas(block.GasLimit())
+		receipts types.Receipts
+		usedGas  = new(uint64)
+		header   = block.Header()
+		allLogs  []*types.Log
+		gp       = new(GasPool).AddGas(block.GasLimit())
 	)
 	// Mutate the the block and state according to any hard-fork specs
 	if p.config.DAOForkSupport && p.config.DAOForkBlock != nil && p.config.DAOForkBlock.Cmp(block.Number()) == 0 {
@@ -70,9 +68,9 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 	// Iterate over and process the individual transactions
 	for i, tx := range block.Transactions() {
 		statedb.Prepare(tx.Hash(), block.Hash(), i)
-		receipt, _, err := ApplyTransaction(p.config, p.bc, nil, gp, statedb, header, tx, totalUsedGas, cfg)
+		receipt, _, err := ApplyTransaction(p.config, p.bc, nil, gp, statedb, header, tx, usedGas, cfg)
 		if err != nil {
-			return nil, nil, nil, err
+			return nil, nil, 0, err
 		}
 		receipts = append(receipts, receipt)
 		allLogs = append(allLogs, receipt.Logs...)
@@ -80,17 +78,17 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 	// Finalize the block, applying any consensus engine specific extras (e.g. block rewards)
 	p.engine.Finalize(p.bc, header, statedb, block.Transactions(), block.Uncles(), receipts)
 
-	return receipts, allLogs, totalUsedGas, nil
+	return receipts, allLogs, *usedGas, nil
 }
 
 // ApplyTransaction attempts to apply a transaction to the given state database
 // and uses the input parameters for its environment. It returns the receipt
 // for the transaction, gas used and an error if the transaction failed,
 // indicating the block was invalid.
-func ApplyTransaction(config *params.ChainConfig, bc *BlockChain, author *common.Address, gp *GasPool, statedb *state.StateDB, header *types.Header, tx *types.Transaction, usedGas *big.Int, cfg vm.Config) (*types.Receipt, *big.Int, error) {
+func ApplyTransaction(config *params.ChainConfig, bc *BlockChain, author *common.Address, gp *GasPool, statedb *state.StateDB, header *types.Header, tx *types.Transaction, usedGas *uint64, cfg vm.Config) (*types.Receipt, uint64, error) {
 	msg, err := tx.AsMessage(types.MakeSigner(config, header.Number))
 	if err != nil {
-		return nil, nil, err
+		return nil, 0, err
 	}
 	// Create a new context to be used in the EVM environment
 	context := NewEVMContext(msg, header, bc, author)
@@ -100,9 +98,8 @@ func ApplyTransaction(config *params.ChainConfig, bc *BlockChain, author *common
 	// Apply the transaction to the current state (included in the env)
 	_, gas, failed, err := ApplyMessage(vmenv, msg, gp)
 	if err != nil {
-		return nil, nil, err
+		return nil, 0, err
 	}
-
 	// Update the state with pending changes
 	var root []byte
 	if config.IsByzantium(header.Number) {
@@ -110,18 +107,17 @@ func ApplyTransaction(config *params.ChainConfig, bc *BlockChain, author *common
 	} else {
 		root = statedb.IntermediateRoot(config.IsEIP158(header.Number)).Bytes()
 	}
-	usedGas.Add(usedGas, gas)
+	*usedGas += gas
 
 	// Create a new receipt for the transaction, storing the intermediate root and gas used by the tx
 	// based on the eip phase, we're passing wether the root touch-delete accounts.
-	receipt := types.NewReceipt(root, failed, usedGas)
+	receipt := types.NewReceipt(root, failed, *usedGas)
 	receipt.TxHash = tx.Hash()
-	receipt.GasUsed = new(big.Int).Set(gas)
+	receipt.GasUsed = gas
 	// if the transaction created a contract, store the creation address in the receipt.
 	if msg.To() == nil {
 		receipt.ContractAddress = crypto.CreateAddress(vmenv.Context.Origin, tx.Nonce())
 	}
-
 	// Set the receipt logs and create a bloom for filtering
 	receipt.Logs = statedb.GetLogs(tx.Hash())
 	receipt.Bloom = types.CreateBloom(types.Receipts{receipt})
diff --git a/core/state_transition.go b/core/state_transition.go
index e7a068589..390473fff 100644
--- a/core/state_transition.go
+++ b/core/state_transition.go
@@ -18,17 +18,16 @@ package core
 
 import (
 	"errors"
+	"math"
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
 )
 
 var (
-	Big0                         = big.NewInt(0)
 	errInsufficientBalanceForGas = errors.New("insufficient balance to pay for gas")
 )
 
@@ -54,7 +53,7 @@ type StateTransition struct {
 	msg        Message
 	gas        uint64
 	gasPrice   *big.Int
-	initialGas *big.Int
+	initialGas uint64
 	value      *big.Int
 	data       []byte
 	state      vm.StateDB
@@ -68,7 +67,7 @@ type Message interface {
 	To() *common.Address
 
 	GasPrice() *big.Int
-	Gas() *big.Int
+	Gas() uint64
 	Value() *big.Int
 
 	Nonce() uint64
@@ -76,45 +75,49 @@ type Message interface {
 	Data() []byte
 }
 
-// IntrinsicGas computes the 'intrinsic gas' for a message
-// with the given data.
-//
-// TODO convert to uint64
-func IntrinsicGas(data []byte, contractCreation, homestead bool) *big.Int {
-	igas := new(big.Int)
+// IntrinsicGas computes the 'intrinsic gas' for a message with the given data.
+func IntrinsicGas(data []byte, contractCreation, homestead bool) (uint64, error) {
+	// Set the starting gas for the raw transaction
+	var gas uint64
 	if contractCreation && homestead {
-		igas.SetUint64(params.TxGasContractCreation)
+		gas = params.TxGasContractCreation
 	} else {
-		igas.SetUint64(params.TxGas)
+		gas = params.TxGas
 	}
+	// Bump the required gas by the amount of transactional data
 	if len(data) > 0 {
-		var nz int64
+		// Zero and non-zero bytes are priced differently
+		var nz uint64
 		for _, byt := range data {
 			if byt != 0 {
 				nz++
 			}
 		}
-		m := big.NewInt(nz)
-		m.Mul(m, new(big.Int).SetUint64(params.TxDataNonZeroGas))
-		igas.Add(igas, m)
-		m.SetInt64(int64(len(data)) - nz)
-		m.Mul(m, new(big.Int).SetUint64(params.TxDataZeroGas))
-		igas.Add(igas, m)
+		// Make sure we don't exceed uint64 for all data combinations
+		if (math.MaxUint64-gas)/params.TxDataNonZeroGas < nz {
+			return 0, vm.ErrOutOfGas
+		}
+		gas += nz * params.TxDataNonZeroGas
+
+		z := uint64(len(data)) - nz
+		if (math.MaxUint64-gas)/params.TxDataZeroGas < z {
+			return 0, vm.ErrOutOfGas
+		}
+		gas += z * params.TxDataZeroGas
 	}
-	return igas
+	return gas, nil
 }
 
 // NewStateTransition initialises and returns a new state transition object.
 func NewStateTransition(evm *vm.EVM, msg Message, gp *GasPool) *StateTransition {
 	return &StateTransition{
-		gp:         gp,
-		evm:        evm,
-		msg:        msg,
-		gasPrice:   msg.GasPrice(),
-		initialGas: new(big.Int),
-		value:      msg.Value(),
-		data:       msg.Data(),
-		state:      evm.StateDB,
+		gp:       gp,
+		evm:      evm,
+		msg:      msg,
+		gasPrice: msg.GasPrice(),
+		value:    msg.Value(),
+		data:     msg.Data(),
+		state:    evm.StateDB,
 	}
 }
 
@@ -125,11 +128,8 @@ func NewStateTransition(evm *vm.EVM, msg Message, gp *GasPool) *StateTransition
 // the gas used (which includes gas refunds) and an error if it failed. An error always
 // indicates a core error meaning that the message would always fail for that particular
 // state and would never be accepted within a block.
-func ApplyMessage(evm *vm.EVM, msg Message, gp *GasPool) ([]byte, *big.Int, bool, error) {
-	st := NewStateTransition(evm, msg, gp)
-
-	ret, _, gasUsed, failed, err := st.TransitionDb()
-	return ret, gasUsed, failed, err
+func ApplyMessage(evm *vm.EVM, msg Message, gp *GasPool) ([]byte, uint64, bool, error) {
+	return NewStateTransition(evm, msg, gp).TransitionDb()
 }
 
 func (st *StateTransition) from() vm.AccountRef {
@@ -166,26 +166,20 @@ func (st *StateTransition) useGas(amount uint64) error {
 }
 
 func (st *StateTransition) buyGas() error {
-	mgas := st.msg.Gas()
-	if mgas.BitLen() > 64 {
-		return vm.ErrOutOfGas
-	}
-
-	mgval := new(big.Int).Mul(mgas, st.gasPrice)
-
 	var (
 		state  = st.state
 		sender = st.from()
 	)
+	mgval := new(big.Int).Mul(new(big.Int).SetUint64(st.msg.Gas()), st.gasPrice)
 	if state.GetBalance(sender.Address()).Cmp(mgval) < 0 {
 		return errInsufficientBalanceForGas
 	}
-	if err := st.gp.SubGas(mgas); err != nil {
+	if err := st.gp.SubGas(st.msg.Gas()); err != nil {
 		return err
 	}
-	st.gas += mgas.Uint64()
+	st.gas += st.msg.Gas()
 
-	st.initialGas.Set(mgas)
+	st.initialGas = st.msg.Gas()
 	state.SubBalance(sender.Address(), mgval)
 	return nil
 }
@@ -206,10 +200,10 @@ func (st *StateTransition) preCheck() error {
 	return st.buyGas()
 }
 
-// TransitionDb will transition the state by applying the current message and returning the result
-// including the required gas for the operation as well as the used gas. It returns an error if it
+// TransitionDb will transition the state by applying the current message and
+// returning the result including the the used gas. It returns an error if it
 // failed. An error indicates a consensus issue.
-func (st *StateTransition) TransitionDb() (ret []byte, requiredGas, usedGas *big.Int, failed bool, err error) {
+func (st *StateTransition) TransitionDb() (ret []byte, usedGas uint64, failed bool, err error) {
 	if err = st.preCheck(); err != nil {
 		return
 	}
@@ -220,13 +214,9 @@ func (st *StateTransition) TransitionDb() (ret []byte, requiredGas, usedGas *big
 	contractCreation := msg.To() == nil
 
 	// Pay intrinsic gas
-	// TODO convert to uint64
-	intrinsicGas := IntrinsicGas(st.data, contractCreation, homestead)
-	if intrinsicGas.BitLen() > 64 {
-		return nil, nil, nil, false, vm.ErrOutOfGas
-	}
-	if err = st.useGas(intrinsicGas.Uint64()); err != nil {
-		return nil, nil, nil, false, err
+	gas, err := IntrinsicGas(st.data, contractCreation, homestead)
+	if err = st.useGas(gas); err != nil {
+		return nil, 0, false, err
 	}
 
 	var (
@@ -249,36 +239,35 @@ func (st *StateTransition) TransitionDb() (ret []byte, requiredGas, usedGas *big
 		// sufficient balance to make the transfer happen. The first
 		// balance transfer may never fail.
 		if vmerr == vm.ErrInsufficientBalance {
-			return nil, nil, nil, false, vmerr
+			return nil, 0, false, vmerr
 		}
 	}
-	requiredGas = new(big.Int).Set(st.gasUsed())
-
 	st.refundGas()
-	st.state.AddBalance(st.evm.Coinbase, new(big.Int).Mul(st.gasUsed(), st.gasPrice))
+	st.state.AddBalance(st.evm.Coinbase, new(big.Int).Mul(new(big.Int).SetUint64(st.gasUsed()), st.gasPrice))
 
-	return ret, requiredGas, st.gasUsed(), vmerr != nil, err
+	return ret, st.gasUsed(), vmerr != nil, err
 }
 
 func (st *StateTransition) refundGas() {
-	// Return eth for remaining gas to the sender account,
-	// exchanged at the original rate.
-	sender := st.from() // err already checked
-	remaining := new(big.Int).Mul(new(big.Int).SetUint64(st.gas), st.gasPrice)
-	st.state.AddBalance(sender.Address(), remaining)
-
 	// Apply refund counter, capped to half of the used gas.
-	uhalf := remaining.Div(st.gasUsed(), common.Big2)
-	refund := math.BigMin(uhalf, st.state.GetRefund())
-	st.gas += refund.Uint64()
+	refund := st.gasUsed() / 2
+	if refund > st.state.GetRefund() {
+		refund = st.state.GetRefund()
+	}
+	st.gas += refund
 
-	st.state.AddBalance(sender.Address(), refund.Mul(refund, st.gasPrice))
+	// Return ETH for remaining gas, exchanged at the original rate.
+	sender := st.from()
+
+	remaining := new(big.Int).Mul(new(big.Int).SetUint64(st.gas), st.gasPrice)
+	st.state.AddBalance(sender.Address(), remaining)
 
 	// Also return remaining gas to the block gas counter so it is
 	// available for the next transaction.
-	st.gp.AddGas(new(big.Int).SetUint64(st.gas))
+	st.gp.AddGas(st.gas)
 }
 
-func (st *StateTransition) gasUsed() *big.Int {
-	return new(big.Int).Sub(st.initialGas, new(big.Int).SetUint64(st.gas))
+// gasUsed returns the amount of gas used up by the state transition.
+func (st *StateTransition) gasUsed() uint64 {
+	return st.initialGas - st.gas
 }
diff --git a/core/tx_list.go b/core/tx_list.go
index 838433b89..55fc42617 100644
--- a/core/tx_list.go
+++ b/core/tx_list.go
@@ -224,7 +224,7 @@ type txList struct {
 	txs    *txSortedMap // Heap indexed sorted hash map of the transactions
 
 	costcap *big.Int // Price of the highest costing transaction (reset only if exceeds balance)
-	gascap  *big.Int // Gas limit of the highest spending transaction (reset only if exceeds block limit)
+	gascap  uint64   // Gas limit of the highest spending transaction (reset only if exceeds block limit)
 }
 
 // newTxList create a new transaction list for maintaining nonce-indexable fast,
@@ -234,7 +234,6 @@ func newTxList(strict bool) *txList {
 		strict:  strict,
 		txs:     newTxSortedMap(),
 		costcap: new(big.Int),
-		gascap:  new(big.Int),
 	}
 }
 
@@ -266,7 +265,7 @@ func (l *txList) Add(tx *types.Transaction, priceBump uint64) (bool, *types.Tran
 	if cost := tx.Cost(); l.costcap.Cmp(cost) < 0 {
 		l.costcap = cost
 	}
-	if gas := tx.Gas(); l.gascap.Cmp(gas) < 0 {
+	if gas := tx.Gas(); l.gascap < gas {
 		l.gascap = gas
 	}
 	return true, old
@@ -288,16 +287,16 @@ func (l *txList) Forward(threshold uint64) types.Transactions {
 // a point in calculating all the costs or if the balance covers all. If the threshold
 // is lower than the costgas cap, the caps will be reset to a new high after removing
 // the newly invalidated transactions.
-func (l *txList) Filter(costLimit, gasLimit *big.Int) (types.Transactions, types.Transactions) {
+func (l *txList) Filter(costLimit *big.Int, gasLimit uint64) (types.Transactions, types.Transactions) {
 	// If all transactions are below the threshold, short circuit
-	if l.costcap.Cmp(costLimit) <= 0 && l.gascap.Cmp(gasLimit) <= 0 {
+	if l.costcap.Cmp(costLimit) <= 0 && l.gascap <= gasLimit {
 		return nil, nil
 	}
 	l.costcap = new(big.Int).Set(costLimit) // Lower the caps to the thresholds
-	l.gascap = new(big.Int).Set(gasLimit)
+	l.gascap = gasLimit
 
 	// Filter out all the transactions above the account's funds
-	removed := l.txs.Filter(func(tx *types.Transaction) bool { return tx.Cost().Cmp(costLimit) > 0 || tx.Gas().Cmp(gasLimit) > 0 })
+	removed := l.txs.Filter(func(tx *types.Transaction) bool { return tx.Cost().Cmp(costLimit) > 0 || tx.Gas() > gasLimit })
 
 	// If the list was strict, filter anything above the lowest nonce
 	var invalids types.Transactions
diff --git a/core/tx_list_test.go b/core/tx_list_test.go
index b4f0b5228..d579f501a 100644
--- a/core/tx_list_test.go
+++ b/core/tx_list_test.go
@@ -17,7 +17,6 @@
 package core
 
 import (
-	"math/big"
 	"math/rand"
 	"testing"
 
@@ -33,7 +32,7 @@ func TestStrictTxListAdd(t *testing.T) {
 
 	txs := make(types.Transactions, 1024)
 	for i := 0; i < len(txs); i++ {
-		txs[i] = transaction(uint64(i), new(big.Int), key)
+		txs[i] = transaction(uint64(i), 0, key)
 	}
 	// Insert the transactions in a random order
 	list := newTxList(true)
diff --git a/core/tx_pool.go b/core/tx_pool.go
index dade5d09f..dc3ddc423 100644
--- a/core/tx_pool.go
+++ b/core/tx_pool.go
@@ -197,7 +197,7 @@ type TxPool struct {
 
 	currentState  *state.StateDB      // Current state in the blockchain head
 	pendingState  *state.ManagedState // Pending state tracking virtual nonces
-	currentMaxGas *big.Int            // Current gas limit for transaction caps
+	currentMaxGas uint64              // Current gas limit for transaction caps
 
 	locals  *accountSet // Set of local transaction to exempt from eviction rules
 	journal *txJournal  // Journal of local transaction to back up to disk
@@ -564,7 +564,7 @@ func (pool *TxPool) validateTx(tx *types.Transaction, local bool) error {
 		return ErrNegativeValue
 	}
 	// Ensure the transaction doesn't exceed the current block limit gas.
-	if pool.currentMaxGas.Cmp(tx.Gas()) < 0 {
+	if pool.currentMaxGas < tx.Gas() {
 		return ErrGasLimit
 	}
 	// Make sure the transaction is signed properly
@@ -586,8 +586,11 @@ func (pool *TxPool) validateTx(tx *types.Transaction, local bool) error {
 	if pool.currentState.GetBalance(from).Cmp(tx.Cost()) < 0 {
 		return ErrInsufficientFunds
 	}
-	intrGas := IntrinsicGas(tx.Data(), tx.To() == nil, pool.homestead)
-	if tx.Gas().Cmp(intrGas) < 0 {
+	intrGas, err := IntrinsicGas(tx.Data(), tx.To() == nil, pool.homestead)
+	if err != nil {
+		return err
+	}
+	if tx.Gas() < intrGas {
 		return ErrIntrinsicGas
 	}
 	return nil
diff --git a/core/tx_pool_test.go b/core/tx_pool_test.go
index 1f193a06c..cd11f2ba2 100644
--- a/core/tx_pool_test.go
+++ b/core/tx_pool_test.go
@@ -46,7 +46,7 @@ func init() {
 
 type testBlockChain struct {
 	statedb       *state.StateDB
-	gasLimit      *big.Int
+	gasLimit      uint64
 	chainHeadFeed *event.Feed
 }
 
@@ -68,11 +68,11 @@ func (bc *testBlockChain) SubscribeChainHeadEvent(ch chan<- ChainHeadEvent) even
 	return bc.chainHeadFeed.Subscribe(ch)
 }
 
-func transaction(nonce uint64, gaslimit *big.Int, key *ecdsa.PrivateKey) *types.Transaction {
+func transaction(nonce uint64, gaslimit uint64, key *ecdsa.PrivateKey) *types.Transaction {
 	return pricedTransaction(nonce, gaslimit, big.NewInt(1), key)
 }
 
-func pricedTransaction(nonce uint64, gaslimit, gasprice *big.Int, key *ecdsa.PrivateKey) *types.Transaction {
+func pricedTransaction(nonce uint64, gaslimit uint64, gasprice *big.Int, key *ecdsa.PrivateKey) *types.Transaction {
 	tx, _ := types.SignTx(types.NewTransaction(nonce, common.Address{}, big.NewInt(100), gaslimit, gasprice, nil), types.HomesteadSigner{}, key)
 	return tx
 }
@@ -80,7 +80,7 @@ func pricedTransaction(nonce uint64, gaslimit, gasprice *big.Int, key *ecdsa.Pri
 func setupTxPool() (*TxPool, *ecdsa.PrivateKey) {
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	key, _ := crypto.GenerateKey()
 	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
@@ -184,10 +184,10 @@ func TestStateChangeDuringTransactionPoolReset(t *testing.T) {
 
 	// setup pool with 2 transaction in it
 	statedb.SetBalance(address, new(big.Int).SetUint64(params.Ether))
-	blockchain := &testChain{&testBlockChain{statedb, big.NewInt(1000000000), new(event.Feed)}, address, &trigger}
+	blockchain := &testChain{&testBlockChain{statedb, 1000000000, new(event.Feed)}, address, &trigger}
 
-	tx0 := transaction(0, big.NewInt(100000), key)
-	tx1 := transaction(1, big.NewInt(100000), key)
+	tx0 := transaction(0, 100000, key)
+	tx1 := transaction(1, 100000, key)
 
 	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
 	defer pool.Stop()
@@ -230,7 +230,7 @@ func TestInvalidTransactions(t *testing.T) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	tx := transaction(0, big.NewInt(100), key)
+	tx := transaction(0, 100, key)
 	from, _ := deriveSender(tx)
 
 	pool.currentState.AddBalance(from, big.NewInt(1))
@@ -238,7 +238,7 @@ func TestInvalidTransactions(t *testing.T) {
 		t.Error("expected", ErrInsufficientFunds)
 	}
 
-	balance := new(big.Int).Add(tx.Value(), new(big.Int).Mul(tx.Gas(), tx.GasPrice()))
+	balance := new(big.Int).Add(tx.Value(), new(big.Int).Mul(new(big.Int).SetUint64(tx.Gas()), tx.GasPrice()))
 	pool.currentState.AddBalance(from, balance)
 	if err := pool.AddRemote(tx); err != ErrIntrinsicGas {
 		t.Error("expected", ErrIntrinsicGas, "got", err)
@@ -246,12 +246,12 @@ func TestInvalidTransactions(t *testing.T) {
 
 	pool.currentState.SetNonce(from, 1)
 	pool.currentState.AddBalance(from, big.NewInt(0xffffffffffffff))
-	tx = transaction(0, big.NewInt(100000), key)
+	tx = transaction(0, 100000, key)
 	if err := pool.AddRemote(tx); err != ErrNonceTooLow {
 		t.Error("expected", ErrNonceTooLow)
 	}
 
-	tx = transaction(1, big.NewInt(100000), key)
+	tx = transaction(1, 100000, key)
 	pool.gasPrice = big.NewInt(1000)
 	if err := pool.AddRemote(tx); err != ErrUnderpriced {
 		t.Error("expected", ErrUnderpriced, "got", err)
@@ -267,7 +267,7 @@ func TestTransactionQueue(t *testing.T) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	tx := transaction(0, big.NewInt(100), key)
+	tx := transaction(0, 100, key)
 	from, _ := deriveSender(tx)
 	pool.currentState.AddBalance(from, big.NewInt(1000))
 	pool.lockedReset(nil, nil)
@@ -278,7 +278,7 @@ func TestTransactionQueue(t *testing.T) {
 		t.Error("expected valid txs to be 1 is", len(pool.pending))
 	}
 
-	tx = transaction(1, big.NewInt(100), key)
+	tx = transaction(1, 100, key)
 	from, _ = deriveSender(tx)
 	pool.currentState.SetNonce(from, 2)
 	pool.enqueueTx(tx.Hash(), tx)
@@ -294,9 +294,9 @@ func TestTransactionQueue(t *testing.T) {
 	pool, key = setupTxPool()
 	defer pool.Stop()
 
-	tx1 := transaction(0, big.NewInt(100), key)
-	tx2 := transaction(10, big.NewInt(100), key)
-	tx3 := transaction(11, big.NewInt(100), key)
+	tx1 := transaction(0, 100, key)
+	tx2 := transaction(10, 100, key)
+	tx3 := transaction(11, 100, key)
 	from, _ = deriveSender(tx1)
 	pool.currentState.AddBalance(from, big.NewInt(1000))
 	pool.lockedReset(nil, nil)
@@ -321,7 +321,7 @@ func TestTransactionNegativeValue(t *testing.T) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	tx, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(-1), big.NewInt(100), big.NewInt(1), nil), types.HomesteadSigner{}, key)
+	tx, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(-1), 100, big.NewInt(1), nil), types.HomesteadSigner{}, key)
 	from, _ := deriveSender(tx)
 	pool.currentState.AddBalance(from, big.NewInt(1))
 	if err := pool.AddRemote(tx); err != ErrNegativeValue {
@@ -341,12 +341,12 @@ func TestTransactionChainFork(t *testing.T) {
 		statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
 		statedb.AddBalance(addr, big.NewInt(100000000000000))
 
-		pool.chain = &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+		pool.chain = &testBlockChain{statedb, 1000000, new(event.Feed)}
 		pool.lockedReset(nil, nil)
 	}
 	resetState()
 
-	tx := transaction(0, big.NewInt(100000), key)
+	tx := transaction(0, 100000, key)
 	if _, err := pool.add(tx, false); err != nil {
 		t.Error("didn't expect error", err)
 	}
@@ -371,15 +371,15 @@ func TestTransactionDoubleNonce(t *testing.T) {
 		statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
 		statedb.AddBalance(addr, big.NewInt(100000000000000))
 
-		pool.chain = &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+		pool.chain = &testBlockChain{statedb, 1000000, new(event.Feed)}
 		pool.lockedReset(nil, nil)
 	}
 	resetState()
 
 	signer := types.HomesteadSigner{}
-	tx1, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(100), big.NewInt(100000), big.NewInt(1), nil), signer, key)
-	tx2, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(100), big.NewInt(1000000), big.NewInt(2), nil), signer, key)
-	tx3, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(100), big.NewInt(1000000), big.NewInt(1), nil), signer, key)
+	tx1, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(100), 100000, big.NewInt(1), nil), signer, key)
+	tx2, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(100), 1000000, big.NewInt(2), nil), signer, key)
+	tx3, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(100), 1000000, big.NewInt(1), nil), signer, key)
 
 	// Add the first two transaction, ensure higher priced stays only
 	if replace, err := pool.add(tx1, false); err != nil || replace {
@@ -418,7 +418,7 @@ func TestTransactionMissingNonce(t *testing.T) {
 
 	addr := crypto.PubkeyToAddress(key.PublicKey)
 	pool.currentState.AddBalance(addr, big.NewInt(100000000000000))
-	tx := transaction(1, big.NewInt(100000), key)
+	tx := transaction(1, 100000, key)
 	if _, err := pool.add(tx, false); err != nil {
 		t.Error("didn't expect error", err)
 	}
@@ -445,7 +445,7 @@ func TestTransactionNonceRecovery(t *testing.T) {
 	pool.currentState.AddBalance(addr, big.NewInt(100000000000000))
 	pool.lockedReset(nil, nil)
 
-	tx := transaction(n, big.NewInt(100000), key)
+	tx := transaction(n, 100000, key)
 	if err := pool.AddRemote(tx); err != nil {
 		t.Error(err)
 	}
@@ -466,17 +466,17 @@ func TestTransactionDropping(t *testing.T) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
+	account, _ := deriveSender(transaction(0, 0, key))
 	pool.currentState.AddBalance(account, big.NewInt(1000))
 
 	// Add some pending and some queued transactions
 	var (
-		tx0  = transaction(0, big.NewInt(100), key)
-		tx1  = transaction(1, big.NewInt(200), key)
-		tx2  = transaction(2, big.NewInt(300), key)
-		tx10 = transaction(10, big.NewInt(100), key)
-		tx11 = transaction(11, big.NewInt(200), key)
-		tx12 = transaction(12, big.NewInt(300), key)
+		tx0  = transaction(0, 100, key)
+		tx1  = transaction(1, 200, key)
+		tx2  = transaction(2, 300, key)
+		tx10 = transaction(10, 100, key)
+		tx11 = transaction(11, 200, key)
+		tx12 = transaction(12, 300, key)
 	)
 	pool.promoteTx(account, tx0.Hash(), tx0)
 	pool.promoteTx(account, tx1.Hash(), tx1)
@@ -531,7 +531,7 @@ func TestTransactionDropping(t *testing.T) {
 		t.Errorf("total transaction mismatch: have %d, want %d", len(pool.all), 4)
 	}
 	// Reduce the block gas limit, check that invalidated transactions are dropped
-	pool.chain.(*testBlockChain).gasLimit = big.NewInt(100)
+	pool.chain.(*testBlockChain).gasLimit = 100
 	pool.lockedReset(nil, nil)
 
 	if _, ok := pool.pending[account].txs.items[tx0.Nonce()]; !ok {
@@ -561,7 +561,7 @@ func TestTransactionPostponing(t *testing.T) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
+	account, _ := deriveSender(transaction(0, 0, key))
 	pool.currentState.AddBalance(account, big.NewInt(1000))
 
 	// Add a batch consecutive pending transactions for validation
@@ -569,9 +569,9 @@ func TestTransactionPostponing(t *testing.T) {
 	for i := 0; i < 100; i++ {
 		var tx *types.Transaction
 		if i%2 == 0 {
-			tx = transaction(uint64(i), big.NewInt(100), key)
+			tx = transaction(uint64(i), 100, key)
 		} else {
-			tx = transaction(uint64(i), big.NewInt(500), key)
+			tx = transaction(uint64(i), 500, key)
 		}
 		pool.promoteTx(account, tx.Hash(), tx)
 		txns = append(txns, tx)
@@ -638,7 +638,7 @@ func TestTransactionGapFilling(t *testing.T) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
+	account, _ := deriveSender(transaction(0, 0, key))
 	pool.currentState.AddBalance(account, big.NewInt(1000000))
 
 	// Keep track of transaction events to ensure all executables get announced
@@ -647,10 +647,10 @@ func TestTransactionGapFilling(t *testing.T) {
 	defer sub.Unsubscribe()
 
 	// Create a pending and a queued transaction with a nonce-gap in between
-	if err := pool.AddRemote(transaction(0, big.NewInt(100000), key)); err != nil {
+	if err := pool.AddRemote(transaction(0, 100000, key)); err != nil {
 		t.Fatalf("failed to add pending transaction: %v", err)
 	}
-	if err := pool.AddRemote(transaction(2, big.NewInt(100000), key)); err != nil {
+	if err := pool.AddRemote(transaction(2, 100000, key)); err != nil {
 		t.Fatalf("failed to add queued transaction: %v", err)
 	}
 	pending, queued := pool.Stats()
@@ -667,7 +667,7 @@ func TestTransactionGapFilling(t *testing.T) {
 		t.Fatalf("pool internal state corrupted: %v", err)
 	}
 	// Fill the nonce gap and ensure all transactions become pending
-	if err := pool.AddRemote(transaction(1, big.NewInt(100000), key)); err != nil {
+	if err := pool.AddRemote(transaction(1, 100000, key)); err != nil {
 		t.Fatalf("failed to add gapped transaction: %v", err)
 	}
 	pending, queued = pool.Stats()
@@ -694,12 +694,12 @@ func TestTransactionQueueAccountLimiting(t *testing.T) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
+	account, _ := deriveSender(transaction(0, 0, key))
 	pool.currentState.AddBalance(account, big.NewInt(1000000))
 
 	// Keep queuing up transactions and make sure all above a limit are dropped
 	for i := uint64(1); i <= testTxPoolConfig.AccountQueue+5; i++ {
-		if err := pool.AddRemote(transaction(i, big.NewInt(100000), key)); err != nil {
+		if err := pool.AddRemote(transaction(i, 100000, key)); err != nil {
 			t.Fatalf("tx %d: failed to add transaction: %v", i, err)
 		}
 		if len(pool.pending) != 0 {
@@ -738,7 +738,7 @@ func testTransactionQueueGlobalLimiting(t *testing.T, nolocals bool) {
 	// Create the pool to test the limit enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.NoLocals = nolocals
@@ -763,7 +763,7 @@ func testTransactionQueueGlobalLimiting(t *testing.T, nolocals bool) {
 		key := keys[rand.Intn(len(keys)-1)] // skip adding transactions with the local account
 		addr := crypto.PubkeyToAddress(key.PublicKey)
 
-		txs = append(txs, transaction(nonces[addr]+1, big.NewInt(100000), key))
+		txs = append(txs, transaction(nonces[addr]+1, 100000, key))
 		nonces[addr]++
 	}
 	// Import the batch and verify that limits have been enforced
@@ -782,7 +782,7 @@ func testTransactionQueueGlobalLimiting(t *testing.T, nolocals bool) {
 	// Generate a batch of transactions from the local account and import them
 	txs = txs[:0]
 	for i := uint64(0); i < 3*config.GlobalQueue; i++ {
-		txs = append(txs, transaction(i+1, big.NewInt(100000), local))
+		txs = append(txs, transaction(i+1, 100000, local))
 	}
 	pool.AddLocals(txs)
 
@@ -827,7 +827,7 @@ func testTransactionQueueTimeLimiting(t *testing.T, nolocals bool) {
 	// Create the pool to test the non-expiration enforcement
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.Lifetime = time.Second
@@ -844,10 +844,10 @@ func testTransactionQueueTimeLimiting(t *testing.T, nolocals bool) {
 	pool.currentState.AddBalance(crypto.PubkeyToAddress(remote.PublicKey), big.NewInt(1000000000))
 
 	// Add the two transactions and ensure they both are queued up
-	if err := pool.AddLocal(pricedTransaction(1, big.NewInt(100000), big.NewInt(1), local)); err != nil {
+	if err := pool.AddLocal(pricedTransaction(1, 100000, big.NewInt(1), local)); err != nil {
 		t.Fatalf("failed to add local transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(1, big.NewInt(100000), big.NewInt(1), remote)); err != nil {
+	if err := pool.AddRemote(pricedTransaction(1, 100000, big.NewInt(1), remote)); err != nil {
 		t.Fatalf("failed to add remote transaction: %v", err)
 	}
 	pending, queued := pool.Stats()
@@ -891,7 +891,7 @@ func TestTransactionPendingLimiting(t *testing.T) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
+	account, _ := deriveSender(transaction(0, 0, key))
 	pool.currentState.AddBalance(account, big.NewInt(1000000))
 
 	// Keep track of transaction events to ensure all executables get announced
@@ -901,7 +901,7 @@ func TestTransactionPendingLimiting(t *testing.T) {
 
 	// Keep queuing up transactions and make sure all above a limit are dropped
 	for i := uint64(0); i < testTxPoolConfig.AccountQueue+5; i++ {
-		if err := pool.AddRemote(transaction(i, big.NewInt(100000), key)); err != nil {
+		if err := pool.AddRemote(transaction(i, 100000, key)); err != nil {
 			t.Fatalf("tx %d: failed to add transaction: %v", i, err)
 		}
 		if pool.pending[account].Len() != int(i)+1 {
@@ -934,11 +934,11 @@ func testTransactionLimitingEquivalency(t *testing.T, origin uint64) {
 	pool1, key1 := setupTxPool()
 	defer pool1.Stop()
 
-	account1, _ := deriveSender(transaction(0, big.NewInt(0), key1))
+	account1, _ := deriveSender(transaction(0, 0, key1))
 	pool1.currentState.AddBalance(account1, big.NewInt(1000000))
 
 	for i := uint64(0); i < testTxPoolConfig.AccountQueue+5; i++ {
-		if err := pool1.AddRemote(transaction(origin+i, big.NewInt(100000), key1)); err != nil {
+		if err := pool1.AddRemote(transaction(origin+i, 100000, key1)); err != nil {
 			t.Fatalf("tx %d: failed to add transaction: %v", i, err)
 		}
 	}
@@ -946,12 +946,12 @@ func testTransactionLimitingEquivalency(t *testing.T, origin uint64) {
 	pool2, key2 := setupTxPool()
 	defer pool2.Stop()
 
-	account2, _ := deriveSender(transaction(0, big.NewInt(0), key2))
+	account2, _ := deriveSender(transaction(0, 0, key2))
 	pool2.currentState.AddBalance(account2, big.NewInt(1000000))
 
 	txns := []*types.Transaction{}
 	for i := uint64(0); i < testTxPoolConfig.AccountQueue+5; i++ {
-		txns = append(txns, transaction(origin+i, big.NewInt(100000), key2))
+		txns = append(txns, transaction(origin+i, 100000, key2))
 	}
 	pool2.AddRemotes(txns)
 
@@ -982,7 +982,7 @@ func TestTransactionPendingGlobalLimiting(t *testing.T) {
 	// Create the pool to test the limit enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.GlobalSlots = config.AccountSlots * 10
@@ -1003,7 +1003,7 @@ func TestTransactionPendingGlobalLimiting(t *testing.T) {
 	for _, key := range keys {
 		addr := crypto.PubkeyToAddress(key.PublicKey)
 		for j := 0; j < int(config.GlobalSlots)/len(keys)*2; j++ {
-			txs = append(txs, transaction(nonces[addr], big.NewInt(100000), key))
+			txs = append(txs, transaction(nonces[addr], 100000, key))
 			nonces[addr]++
 		}
 	}
@@ -1029,7 +1029,7 @@ func TestTransactionCapClearsFromAll(t *testing.T) {
 	// Create the pool to test the limit enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.AccountSlots = 2
@@ -1046,7 +1046,7 @@ func TestTransactionCapClearsFromAll(t *testing.T) {
 
 	txs := types.Transactions{}
 	for j := 0; j < int(config.GlobalSlots)*2; j++ {
-		txs = append(txs, transaction(uint64(j), big.NewInt(100000), key))
+		txs = append(txs, transaction(uint64(j), 100000, key))
 	}
 	// Import the batch and verify that limits have been enforced
 	pool.AddRemotes(txs)
@@ -1064,7 +1064,7 @@ func TestTransactionPendingMinimumAllowance(t *testing.T) {
 	// Create the pool to test the limit enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.GlobalSlots = 0
@@ -1085,7 +1085,7 @@ func TestTransactionPendingMinimumAllowance(t *testing.T) {
 	for _, key := range keys {
 		addr := crypto.PubkeyToAddress(key.PublicKey)
 		for j := 0; j < int(config.AccountSlots)*2; j++ {
-			txs = append(txs, transaction(nonces[addr], big.NewInt(100000), key))
+			txs = append(txs, transaction(nonces[addr], 100000, key))
 			nonces[addr]++
 		}
 	}
@@ -1113,7 +1113,7 @@ func TestTransactionPoolRepricing(t *testing.T) {
 	// Create the pool to test the pricing enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
 	defer pool.Stop()
@@ -1132,15 +1132,15 @@ func TestTransactionPoolRepricing(t *testing.T) {
 	// Generate and queue a batch of transactions, both pending and queued
 	txs := types.Transactions{}
 
-	txs = append(txs, pricedTransaction(0, big.NewInt(100000), big.NewInt(2), keys[0]))
-	txs = append(txs, pricedTransaction(1, big.NewInt(100000), big.NewInt(1), keys[0]))
-	txs = append(txs, pricedTransaction(2, big.NewInt(100000), big.NewInt(2), keys[0]))
+	txs = append(txs, pricedTransaction(0, 100000, big.NewInt(2), keys[0]))
+	txs = append(txs, pricedTransaction(1, 100000, big.NewInt(1), keys[0]))
+	txs = append(txs, pricedTransaction(2, 100000, big.NewInt(2), keys[0]))
 
-	txs = append(txs, pricedTransaction(1, big.NewInt(100000), big.NewInt(2), keys[1]))
-	txs = append(txs, pricedTransaction(2, big.NewInt(100000), big.NewInt(1), keys[1]))
-	txs = append(txs, pricedTransaction(3, big.NewInt(100000), big.NewInt(2), keys[1]))
+	txs = append(txs, pricedTransaction(1, 100000, big.NewInt(2), keys[1]))
+	txs = append(txs, pricedTransaction(2, 100000, big.NewInt(1), keys[1]))
+	txs = append(txs, pricedTransaction(3, 100000, big.NewInt(2), keys[1]))
 
-	ltx := pricedTransaction(0, big.NewInt(100000), big.NewInt(1), keys[2])
+	ltx := pricedTransaction(0, 100000, big.NewInt(1), keys[2])
 
 	// Import the batch and that both pending and queued transactions match up
 	pool.AddRemotes(txs)
@@ -1176,10 +1176,10 @@ func TestTransactionPoolRepricing(t *testing.T) {
 		t.Fatalf("pool internal state corrupted: %v", err)
 	}
 	// Check that we can't add the old transactions back
-	if err := pool.AddRemote(pricedTransaction(1, big.NewInt(100000), big.NewInt(1), keys[0])); err != ErrUnderpriced {
+	if err := pool.AddRemote(pricedTransaction(1, 100000, big.NewInt(1), keys[0])); err != ErrUnderpriced {
 		t.Fatalf("adding underpriced pending transaction error mismatch: have %v, want %v", err, ErrUnderpriced)
 	}
-	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100000), big.NewInt(1), keys[1])); err != ErrUnderpriced {
+	if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(1), keys[1])); err != ErrUnderpriced {
 		t.Fatalf("adding underpriced queued transaction error mismatch: have %v, want %v", err, ErrUnderpriced)
 	}
 	if err := validateEvents(events, 0); err != nil {
@@ -1189,7 +1189,7 @@ func TestTransactionPoolRepricing(t *testing.T) {
 		t.Fatalf("pool internal state corrupted: %v", err)
 	}
 	// However we can add local underpriced transactions
-	tx := pricedTransaction(1, big.NewInt(100000), big.NewInt(1), keys[2])
+	tx := pricedTransaction(1, 100000, big.NewInt(1), keys[2])
 	if err := pool.AddLocal(tx); err != nil {
 		t.Fatalf("failed to add underpriced local transaction: %v", err)
 	}
@@ -1212,7 +1212,7 @@ func TestTransactionPoolRepricingKeepsLocals(t *testing.T) {
 	// Create the pool to test the pricing enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
 	defer pool.Stop()
@@ -1226,12 +1226,12 @@ func TestTransactionPoolRepricingKeepsLocals(t *testing.T) {
 	// Create transaction (both pending and queued) with a linearly growing gasprice
 	for i := uint64(0); i < 500; i++ {
 		// Add pending
-		p_tx := pricedTransaction(i, big.NewInt(100000), big.NewInt(int64(i)), keys[2])
+		p_tx := pricedTransaction(i, 100000, big.NewInt(int64(i)), keys[2])
 		if err := pool.AddLocal(p_tx); err != nil {
 			t.Fatal(err)
 		}
 		// Add queued
-		q_tx := pricedTransaction(i+501, big.NewInt(100000), big.NewInt(int64(i)), keys[2])
+		q_tx := pricedTransaction(i+501, 100000, big.NewInt(int64(i)), keys[2])
 		if err := pool.AddLocal(q_tx); err != nil {
 			t.Fatal(err)
 		}
@@ -1275,7 +1275,7 @@ func TestTransactionPoolUnderpricing(t *testing.T) {
 	// Create the pool to test the pricing enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.GlobalSlots = 2
@@ -1298,12 +1298,12 @@ func TestTransactionPoolUnderpricing(t *testing.T) {
 	// Generate and queue a batch of transactions, both pending and queued
 	txs := types.Transactions{}
 
-	txs = append(txs, pricedTransaction(0, big.NewInt(100000), big.NewInt(1), keys[0]))
-	txs = append(txs, pricedTransaction(1, big.NewInt(100000), big.NewInt(2), keys[0]))
+	txs = append(txs, pricedTransaction(0, 100000, big.NewInt(1), keys[0]))
+	txs = append(txs, pricedTransaction(1, 100000, big.NewInt(2), keys[0]))
 
-	txs = append(txs, pricedTransaction(1, big.NewInt(100000), big.NewInt(1), keys[1]))
+	txs = append(txs, pricedTransaction(1, 100000, big.NewInt(1), keys[1]))
 
-	ltx := pricedTransaction(0, big.NewInt(100000), big.NewInt(1), keys[2])
+	ltx := pricedTransaction(0, 100000, big.NewInt(1), keys[2])
 
 	// Import the batch and that both pending and queued transactions match up
 	pool.AddRemotes(txs)
@@ -1323,17 +1323,17 @@ func TestTransactionPoolUnderpricing(t *testing.T) {
 		t.Fatalf("pool internal state corrupted: %v", err)
 	}
 	// Ensure that adding an underpriced transaction on block limit fails
-	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100000), big.NewInt(1), keys[1])); err != ErrUnderpriced {
+	if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(1), keys[1])); err != ErrUnderpriced {
 		t.Fatalf("adding underpriced pending transaction error mismatch: have %v, want %v", err, ErrUnderpriced)
 	}
 	// Ensure that adding high priced transactions drops cheap ones, but not own
-	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100000), big.NewInt(3), keys[1])); err != nil {
+	if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(3), keys[1])); err != nil {
 		t.Fatalf("failed to add well priced transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100000), big.NewInt(4), keys[1])); err != nil {
+	if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(4), keys[1])); err != nil {
 		t.Fatalf("failed to add well priced transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(3, big.NewInt(100000), big.NewInt(5), keys[1])); err != nil {
+	if err := pool.AddRemote(pricedTransaction(3, 100000, big.NewInt(5), keys[1])); err != nil {
 		t.Fatalf("failed to add well priced transaction: %v", err)
 	}
 	pending, queued = pool.Stats()
@@ -1350,7 +1350,7 @@ func TestTransactionPoolUnderpricing(t *testing.T) {
 		t.Fatalf("pool internal state corrupted: %v", err)
 	}
 	// Ensure that adding local transactions can push out even higher priced ones
-	tx := pricedTransaction(1, big.NewInt(100000), big.NewInt(0), keys[2])
+	tx := pricedTransaction(1, 100000, big.NewInt(0), keys[2])
 	if err := pool.AddLocal(tx); err != nil {
 		t.Fatalf("failed to add underpriced local transaction: %v", err)
 	}
@@ -1377,7 +1377,7 @@ func TestTransactionReplacement(t *testing.T) {
 	// Create the pool to test the pricing enforcement with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
 	defer pool.Stop()
@@ -1395,49 +1395,49 @@ func TestTransactionReplacement(t *testing.T) {
 	price := int64(100)
 	threshold := (price * (100 + int64(testTxPoolConfig.PriceBump))) / 100
 
-	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100000), big.NewInt(1), key)); err != nil {
+	if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(1), key)); err != nil {
 		t.Fatalf("failed to add original cheap pending transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100001), big.NewInt(1), key)); err != ErrReplaceUnderpriced {
+	if err := pool.AddRemote(pricedTransaction(0, 100001, big.NewInt(1), key)); err != ErrReplaceUnderpriced {
 		t.Fatalf("original cheap pending transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
 	}
-	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100000), big.NewInt(2), key)); err != nil {
+	if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(2), key)); err != nil {
 		t.Fatalf("failed to replace original cheap pending transaction: %v", err)
 	}
 	if err := validateEvents(events, 2); err != nil {
 		t.Fatalf("cheap replacement event firing failed: %v", err)
 	}
 
-	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100000), big.NewInt(price), key)); err != nil {
+	if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(price), key)); err != nil {
 		t.Fatalf("failed to add original proper pending transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100001), big.NewInt(threshold-1), key)); err != ErrReplaceUnderpriced {
+	if err := pool.AddRemote(pricedTransaction(0, 100001, big.NewInt(threshold-1), key)); err != ErrReplaceUnderpriced {
 		t.Fatalf("original proper pending transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
 	}
-	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100000), big.NewInt(threshold), key)); err != nil {
+	if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(threshold), key)); err != nil {
 		t.Fatalf("failed to replace original proper pending transaction: %v", err)
 	}
 	if err := validateEvents(events, 2); err != nil {
 		t.Fatalf("proper replacement event firing failed: %v", err)
 	}
 	// Add queued transactions, ensuring the minimum price bump is enforced for replacement (for ultra low prices too)
-	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100000), big.NewInt(1), key)); err != nil {
+	if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(1), key)); err != nil {
 		t.Fatalf("failed to add original cheap queued transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100001), big.NewInt(1), key)); err != ErrReplaceUnderpriced {
+	if err := pool.AddRemote(pricedTransaction(2, 100001, big.NewInt(1), key)); err != ErrReplaceUnderpriced {
 		t.Fatalf("original cheap queued transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
 	}
-	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100000), big.NewInt(2), key)); err != nil {
+	if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(2), key)); err != nil {
 		t.Fatalf("failed to replace original cheap queued transaction: %v", err)
 	}
 
-	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100000), big.NewInt(price), key)); err != nil {
+	if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(price), key)); err != nil {
 		t.Fatalf("failed to add original proper queued transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100001), big.NewInt(threshold-1), key)); err != ErrReplaceUnderpriced {
+	if err := pool.AddRemote(pricedTransaction(2, 100001, big.NewInt(threshold-1), key)); err != ErrReplaceUnderpriced {
 		t.Fatalf("original proper queued transaction replacement error mismatch: have %v, want %v", err, ErrReplaceUnderpriced)
 	}
-	if err := pool.AddRemote(pricedTransaction(2, big.NewInt(100000), big.NewInt(threshold), key)); err != nil {
+	if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(threshold), key)); err != nil {
 		t.Fatalf("failed to replace original proper queued transaction: %v", err)
 	}
 
@@ -1472,7 +1472,7 @@ func testTransactionJournaling(t *testing.T, nolocals bool) {
 	// Create the original pool to inject transaction into the journal
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	config := testTxPoolConfig
 	config.NoLocals = nolocals
@@ -1489,16 +1489,16 @@ func testTransactionJournaling(t *testing.T, nolocals bool) {
 	pool.currentState.AddBalance(crypto.PubkeyToAddress(remote.PublicKey), big.NewInt(1000000000))
 
 	// Add three local and a remote transactions and ensure they are queued up
-	if err := pool.AddLocal(pricedTransaction(0, big.NewInt(100000), big.NewInt(1), local)); err != nil {
+	if err := pool.AddLocal(pricedTransaction(0, 100000, big.NewInt(1), local)); err != nil {
 		t.Fatalf("failed to add local transaction: %v", err)
 	}
-	if err := pool.AddLocal(pricedTransaction(1, big.NewInt(100000), big.NewInt(1), local)); err != nil {
+	if err := pool.AddLocal(pricedTransaction(1, 100000, big.NewInt(1), local)); err != nil {
 		t.Fatalf("failed to add local transaction: %v", err)
 	}
-	if err := pool.AddLocal(pricedTransaction(2, big.NewInt(100000), big.NewInt(1), local)); err != nil {
+	if err := pool.AddLocal(pricedTransaction(2, 100000, big.NewInt(1), local)); err != nil {
 		t.Fatalf("failed to add local transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(0, big.NewInt(100000), big.NewInt(1), remote)); err != nil {
+	if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(1), remote)); err != nil {
 		t.Fatalf("failed to add remote transaction: %v", err)
 	}
 	pending, queued := pool.Stats()
@@ -1514,7 +1514,7 @@ func testTransactionJournaling(t *testing.T, nolocals bool) {
 	// Terminate the old pool, bump the local nonce, create a new pool and ensure relevant transaction survive
 	pool.Stop()
 	statedb.SetNonce(crypto.PubkeyToAddress(local.PublicKey), 1)
-	blockchain = &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain = &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	pool = NewTxPool(config, params.TestChainConfig, blockchain)
 
@@ -1541,7 +1541,7 @@ func testTransactionJournaling(t *testing.T, nolocals bool) {
 	pool.Stop()
 
 	statedb.SetNonce(crypto.PubkeyToAddress(local.PublicKey), 1)
-	blockchain = &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain = &testBlockChain{statedb, 1000000, new(event.Feed)}
 	pool = NewTxPool(config, params.TestChainConfig, blockchain)
 
 	pending, queued = pool.Stats()
@@ -1571,7 +1571,7 @@ func TestTransactionStatusCheck(t *testing.T) {
 	// Create the pool to test the status retrievals with
 	db, _ := ethdb.NewMemDatabase()
 	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
-	blockchain := &testBlockChain{statedb, big.NewInt(1000000), new(event.Feed)}
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
 
 	pool := NewTxPool(testTxPoolConfig, params.TestChainConfig, blockchain)
 	defer pool.Stop()
@@ -1585,10 +1585,10 @@ func TestTransactionStatusCheck(t *testing.T) {
 	// Generate and queue a batch of transactions, both pending and queued
 	txs := types.Transactions{}
 
-	txs = append(txs, pricedTransaction(0, big.NewInt(100000), big.NewInt(1), keys[0])) // Pending only
-	txs = append(txs, pricedTransaction(0, big.NewInt(100000), big.NewInt(1), keys[1])) // Pending and queued
-	txs = append(txs, pricedTransaction(2, big.NewInt(100000), big.NewInt(1), keys[1]))
-	txs = append(txs, pricedTransaction(2, big.NewInt(100000), big.NewInt(1), keys[2])) // Queued only
+	txs = append(txs, pricedTransaction(0, 100000, big.NewInt(1), keys[0])) // Pending only
+	txs = append(txs, pricedTransaction(0, 100000, big.NewInt(1), keys[1])) // Pending and queued
+	txs = append(txs, pricedTransaction(2, 100000, big.NewInt(1), keys[1]))
+	txs = append(txs, pricedTransaction(2, 100000, big.NewInt(1), keys[2])) // Queued only
 
 	// Import the transaction and ensure they are correctly added
 	pool.AddRemotes(txs)
@@ -1631,11 +1631,11 @@ func benchmarkPendingDemotion(b *testing.B, size int) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
+	account, _ := deriveSender(transaction(0, 0, key))
 	pool.currentState.AddBalance(account, big.NewInt(1000000))
 
 	for i := 0; i < size; i++ {
-		tx := transaction(uint64(i), big.NewInt(100000), key)
+		tx := transaction(uint64(i), 100000, key)
 		pool.promoteTx(account, tx.Hash(), tx)
 	}
 	// Benchmark the speed of pool validation
@@ -1656,11 +1656,11 @@ func benchmarkFuturePromotion(b *testing.B, size int) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
+	account, _ := deriveSender(transaction(0, 0, key))
 	pool.currentState.AddBalance(account, big.NewInt(1000000))
 
 	for i := 0; i < size; i++ {
-		tx := transaction(uint64(1+i), big.NewInt(100000), key)
+		tx := transaction(uint64(1+i), 100000, key)
 		pool.enqueueTx(tx.Hash(), tx)
 	}
 	// Benchmark the speed of pool validation
@@ -1676,12 +1676,12 @@ func BenchmarkPoolInsert(b *testing.B) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
+	account, _ := deriveSender(transaction(0, 0, key))
 	pool.currentState.AddBalance(account, big.NewInt(1000000))
 
 	txs := make(types.Transactions, b.N)
 	for i := 0; i < b.N; i++ {
-		txs[i] = transaction(uint64(i), big.NewInt(100000), key)
+		txs[i] = transaction(uint64(i), 100000, key)
 	}
 	// Benchmark importing the transactions into the queue
 	b.ResetTimer()
@@ -1700,14 +1700,14 @@ func benchmarkPoolBatchInsert(b *testing.B, size int) {
 	pool, key := setupTxPool()
 	defer pool.Stop()
 
-	account, _ := deriveSender(transaction(0, big.NewInt(0), key))
+	account, _ := deriveSender(transaction(0, 0, key))
 	pool.currentState.AddBalance(account, big.NewInt(1000000))
 
 	batches := make([]types.Transactions, b.N)
 	for i := 0; i < b.N; i++ {
 		batches[i] = make(types.Transactions, size)
 		for j := 0; j < size; j++ {
-			batches[i][j] = transaction(uint64(size*i+j), big.NewInt(100000), key)
+			batches[i][j] = transaction(uint64(size*i+j), 100000, key)
 		}
 	}
 	// Benchmark importing the transactions into the queue
diff --git a/core/types.go b/core/types.go
index 1cfbbab29..d0bbaf0aa 100644
--- a/core/types.go
+++ b/core/types.go
@@ -17,8 +17,6 @@
 package core
 
 import (
-	"math/big"
-
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
@@ -34,7 +32,7 @@ type Validator interface {
 
 	// ValidateState validates the given statedb and optionally the receipts and
 	// gas used.
-	ValidateState(block, parent *types.Block, state *state.StateDB, receipts types.Receipts, usedGas *big.Int) error
+	ValidateState(block, parent *types.Block, state *state.StateDB, receipts types.Receipts, usedGas uint64) error
 }
 
 // Processor is an interface for processing blocks using a given initial state.
@@ -44,5 +42,5 @@ type Validator interface {
 // of gas used in the process and return an error if any of the internal rules
 // failed.
 type Processor interface {
-	Process(block *types.Block, statedb *state.StateDB, cfg vm.Config) (types.Receipts, []*types.Log, *big.Int, error)
+	Process(block *types.Block, statedb *state.StateDB, cfg vm.Config) (types.Receipts, []*types.Log, uint64, error)
 }
diff --git a/core/types/block.go b/core/types/block.go
index 1d00d9f93..9be62b9e0 100644
--- a/core/types/block.go
+++ b/core/types/block.go
@@ -77,8 +77,8 @@ type Header struct {
 	Bloom       Bloom          `json:"logsBloom"        gencodec:"required"`
 	Difficulty  *big.Int       `json:"difficulty"       gencodec:"required"`
 	Number      *big.Int       `json:"number"           gencodec:"required"`
-	GasLimit    *big.Int       `json:"gasLimit"         gencodec:"required"`
-	GasUsed     *big.Int       `json:"gasUsed"          gencodec:"required"`
+	GasLimit    uint64         `json:"gasLimit"         gencodec:"required"`
+	GasUsed     uint64         `json:"gasUsed"          gencodec:"required"`
 	Time        *big.Int       `json:"timestamp"        gencodec:"required"`
 	Extra       []byte         `json:"extraData"        gencodec:"required"`
 	MixDigest   common.Hash    `json:"mixHash"          gencodec:"required"`
@@ -89,8 +89,8 @@ type Header struct {
 type headerMarshaling struct {
 	Difficulty *hexutil.Big
 	Number     *hexutil.Big
-	GasLimit   *hexutil.Big
-	GasUsed    *hexutil.Big
+	GasLimit   *hexutil.Uint64
+	GasUsed    *hexutil.Uint64
 	Time       *hexutil.Big
 	Extra      hexutil.Bytes
 	Hash       common.Hash `json:"hash"` // adds call to Hash() in MarshalJSON
@@ -243,12 +243,6 @@ func CopyHeader(h *Header) *Header {
 	if cpy.Number = new(big.Int); h.Number != nil {
 		cpy.Number.Set(h.Number)
 	}
-	if cpy.GasLimit = new(big.Int); h.GasLimit != nil {
-		cpy.GasLimit.Set(h.GasLimit)
-	}
-	if cpy.GasUsed = new(big.Int); h.GasUsed != nil {
-		cpy.GasUsed.Set(h.GasUsed)
-	}
 	if len(h.Extra) > 0 {
 		cpy.Extra = make([]byte, len(h.Extra))
 		copy(cpy.Extra, h.Extra)
@@ -302,8 +296,8 @@ func (b *Block) Transaction(hash common.Hash) *Transaction {
 }
 
 func (b *Block) Number() *big.Int     { return new(big.Int).Set(b.header.Number) }
-func (b *Block) GasLimit() *big.Int   { return new(big.Int).Set(b.header.GasLimit) }
-func (b *Block) GasUsed() *big.Int    { return new(big.Int).Set(b.header.GasUsed) }
+func (b *Block) GasLimit() uint64     { return b.header.GasLimit }
+func (b *Block) GasUsed() uint64      { return b.header.GasUsed }
 func (b *Block) Difficulty() *big.Int { return new(big.Int).Set(b.header.Difficulty) }
 func (b *Block) Time() *big.Int       { return new(big.Int).Set(b.header.Time) }
 
diff --git a/core/types/block_test.go b/core/types/block_test.go
index 93435ca00..a35fbc25b 100644
--- a/core/types/block_test.go
+++ b/core/types/block_test.go
@@ -41,8 +41,8 @@ func TestBlockEncoding(t *testing.T) {
 		}
 	}
 	check("Difficulty", block.Difficulty(), big.NewInt(131072))
-	check("GasLimit", block.GasLimit(), big.NewInt(3141592))
-	check("GasUsed", block.GasUsed(), big.NewInt(21000))
+	check("GasLimit", block.GasLimit(), uint64(3141592))
+	check("GasUsed", block.GasUsed(), uint64(21000))
 	check("Coinbase", block.Coinbase(), common.HexToAddress("8888f1f195afa192cfee860698584c030f4c9db1"))
 	check("MixDigest", block.MixDigest(), common.HexToHash("bd4472abb6659ebe3ee06ee4d7b72a00a9f4d001caca51342001075469aff498"))
 	check("Root", block.Root(), common.HexToHash("ef1552a40b7165c3cd773806b9e0c165b75356e0314bf0706f279c729f51e017"))
@@ -51,7 +51,7 @@ func TestBlockEncoding(t *testing.T) {
 	check("Time", block.Time(), big.NewInt(1426516743))
 	check("Size", block.Size(), common.StorageSize(len(blockEnc)))
 
-	tx1 := NewTransaction(0, common.HexToAddress("095e7baea6a6c7c4c2dfeb977efac326af552d87"), big.NewInt(10), big.NewInt(50000), big.NewInt(10), nil)
+	tx1 := NewTransaction(0, common.HexToAddress("095e7baea6a6c7c4c2dfeb977efac326af552d87"), big.NewInt(10), 50000, big.NewInt(10), nil)
 
 	tx1, _ = tx1.WithSignature(HomesteadSigner{}, common.Hex2Bytes("9bea4c4daac7c7c52e093e6a4c35dbbcf8856f1af7b059ba20253e70848d094f8a8fae537ce25ed8cb5af9adac3f141af69bd515bd2ba031522df09b97dd72b100"))
 	fmt.Println(block.Transactions()[0].Hash())
diff --git a/core/types/gen_header_json.go b/core/types/gen_header_json.go
index bcff7a940..8af059104 100644
--- a/core/types/gen_header_json.go
+++ b/core/types/gen_header_json.go
@@ -22,8 +22,8 @@ func (h Header) MarshalJSON() ([]byte, error) {
 		Bloom       Bloom          `json:"logsBloom"        gencodec:"required"`
 		Difficulty  *hexutil.Big   `json:"difficulty"       gencodec:"required"`
 		Number      *hexutil.Big   `json:"number"           gencodec:"required"`
-		GasLimit    *hexutil.Big   `json:"gasLimit"         gencodec:"required"`
-		GasUsed     *hexutil.Big   `json:"gasUsed"          gencodec:"required"`
+		GasLimit    hexutil.Uint64 `json:"gasLimit"         gencodec:"required"`
+		GasUsed     hexutil.Uint64 `json:"gasUsed"          gencodec:"required"`
 		Time        *hexutil.Big   `json:"timestamp"        gencodec:"required"`
 		Extra       hexutil.Bytes  `json:"extraData"        gencodec:"required"`
 		MixDigest   common.Hash    `json:"mixHash"          gencodec:"required"`
@@ -40,8 +40,8 @@ func (h Header) MarshalJSON() ([]byte, error) {
 	enc.Bloom = h.Bloom
 	enc.Difficulty = (*hexutil.Big)(h.Difficulty)
 	enc.Number = (*hexutil.Big)(h.Number)
-	enc.GasLimit = (*hexutil.Big)(h.GasLimit)
-	enc.GasUsed = (*hexutil.Big)(h.GasUsed)
+	enc.GasLimit = hexutil.Uint64(h.GasLimit)
+	enc.GasUsed = hexutil.Uint64(h.GasUsed)
 	enc.Time = (*hexutil.Big)(h.Time)
 	enc.Extra = h.Extra
 	enc.MixDigest = h.MixDigest
@@ -61,8 +61,8 @@ func (h *Header) UnmarshalJSON(input []byte) error {
 		Bloom       *Bloom          `json:"logsBloom"        gencodec:"required"`
 		Difficulty  *hexutil.Big    `json:"difficulty"       gencodec:"required"`
 		Number      *hexutil.Big    `json:"number"           gencodec:"required"`
-		GasLimit    *hexutil.Big    `json:"gasLimit"         gencodec:"required"`
-		GasUsed     *hexutil.Big    `json:"gasUsed"          gencodec:"required"`
+		GasLimit    *hexutil.Uint64 `json:"gasLimit"         gencodec:"required"`
+		GasUsed     *hexutil.Uint64 `json:"gasUsed"          gencodec:"required"`
 		Time        *hexutil.Big    `json:"timestamp"        gencodec:"required"`
 		Extra       hexutil.Bytes   `json:"extraData"        gencodec:"required"`
 		MixDigest   *common.Hash    `json:"mixHash"          gencodec:"required"`
@@ -111,11 +111,11 @@ func (h *Header) UnmarshalJSON(input []byte) error {
 	if dec.GasLimit == nil {
 		return errors.New("missing required field 'gasLimit' for Header")
 	}
-	h.GasLimit = (*big.Int)(dec.GasLimit)
+	h.GasLimit = (uint64)(*dec.GasLimit)
 	if dec.GasUsed == nil {
 		return errors.New("missing required field 'gasUsed' for Header")
 	}
-	h.GasUsed = (*big.Int)(dec.GasUsed)
+	h.GasUsed = (uint64)(*dec.GasUsed)
 	if dec.Time == nil {
 		return errors.New("missing required field 'timestamp' for Header")
 	}
diff --git a/core/types/gen_receipt_json.go b/core/types/gen_receipt_json.go
index b95d99c95..520966874 100644
--- a/core/types/gen_receipt_json.go
+++ b/core/types/gen_receipt_json.go
@@ -5,7 +5,6 @@ package types
 import (
 	"encoding/json"
 	"errors"
-	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
@@ -15,22 +14,22 @@ func (r Receipt) MarshalJSON() ([]byte, error) {
 	type Receipt struct {
 		PostState         hexutil.Bytes  `json:"root"`
 		Status            hexutil.Uint   `json:"status"`
-		CumulativeGasUsed *hexutil.Big   `json:"cumulativeGasUsed" gencodec:"required"`
+		CumulativeGasUsed hexutil.Uint64 `json:"cumulativeGasUsed" gencodec:"required"`
 		Bloom             Bloom          `json:"logsBloom"         gencodec:"required"`
 		Logs              []*Log         `json:"logs"              gencodec:"required"`
 		TxHash            common.Hash    `json:"transactionHash" gencodec:"required"`
 		ContractAddress   common.Address `json:"contractAddress"`
-		GasUsed           *hexutil.Big   `json:"gasUsed" gencodec:"required"`
+		GasUsed           hexutil.Uint64 `json:"gasUsed" gencodec:"required"`
 	}
 	var enc Receipt
 	enc.PostState = r.PostState
 	enc.Status = hexutil.Uint(r.Status)
-	enc.CumulativeGasUsed = (*hexutil.Big)(r.CumulativeGasUsed)
+	enc.CumulativeGasUsed = hexutil.Uint64(r.CumulativeGasUsed)
 	enc.Bloom = r.Bloom
 	enc.Logs = r.Logs
 	enc.TxHash = r.TxHash
 	enc.ContractAddress = r.ContractAddress
-	enc.GasUsed = (*hexutil.Big)(r.GasUsed)
+	enc.GasUsed = hexutil.Uint64(r.GasUsed)
 	return json.Marshal(&enc)
 }
 
@@ -38,12 +37,12 @@ func (r *Receipt) UnmarshalJSON(input []byte) error {
 	type Receipt struct {
 		PostState         hexutil.Bytes   `json:"root"`
 		Status            *hexutil.Uint   `json:"status"`
-		CumulativeGasUsed *hexutil.Big    `json:"cumulativeGasUsed" gencodec:"required"`
+		CumulativeGasUsed *hexutil.Uint64 `json:"cumulativeGasUsed" gencodec:"required"`
 		Bloom             *Bloom          `json:"logsBloom"         gencodec:"required"`
 		Logs              []*Log          `json:"logs"              gencodec:"required"`
 		TxHash            *common.Hash    `json:"transactionHash" gencodec:"required"`
 		ContractAddress   *common.Address `json:"contractAddress"`
-		GasUsed           *hexutil.Big    `json:"gasUsed" gencodec:"required"`
+		GasUsed           *hexutil.Uint64 `json:"gasUsed" gencodec:"required"`
 	}
 	var dec Receipt
 	if err := json.Unmarshal(input, &dec); err != nil {
@@ -58,7 +57,7 @@ func (r *Receipt) UnmarshalJSON(input []byte) error {
 	if dec.CumulativeGasUsed == nil {
 		return errors.New("missing required field 'cumulativeGasUsed' for Receipt")
 	}
-	r.CumulativeGasUsed = (*big.Int)(dec.CumulativeGasUsed)
+	r.CumulativeGasUsed = uint64(*dec.CumulativeGasUsed)
 	if dec.Bloom == nil {
 		return errors.New("missing required field 'logsBloom' for Receipt")
 	}
@@ -77,6 +76,6 @@ func (r *Receipt) UnmarshalJSON(input []byte) error {
 	if dec.GasUsed == nil {
 		return errors.New("missing required field 'gasUsed' for Receipt")
 	}
-	r.GasUsed = (*big.Int)(dec.GasUsed)
+	r.GasUsed = uint64(*dec.GasUsed)
 	return nil
 }
diff --git a/core/types/gen_tx_json.go b/core/types/gen_tx_json.go
index 4fb658e0d..a82822c36 100644
--- a/core/types/gen_tx_json.go
+++ b/core/types/gen_tx_json.go
@@ -15,7 +15,7 @@ func (t txdata) MarshalJSON() ([]byte, error) {
 	type txdata struct {
 		AccountNonce hexutil.Uint64  `json:"nonce"    gencodec:"required"`
 		Price        *hexutil.Big    `json:"gasPrice" gencodec:"required"`
-		GasLimit     *hexutil.Big    `json:"gas"      gencodec:"required"`
+		GasLimit     hexutil.Uint64  `json:"gas"      gencodec:"required"`
 		Recipient    *common.Address `json:"to"       rlp:"nil"`
 		Amount       *hexutil.Big    `json:"value"    gencodec:"required"`
 		Payload      hexutil.Bytes   `json:"input"    gencodec:"required"`
@@ -27,7 +27,7 @@ func (t txdata) MarshalJSON() ([]byte, error) {
 	var enc txdata
 	enc.AccountNonce = hexutil.Uint64(t.AccountNonce)
 	enc.Price = (*hexutil.Big)(t.Price)
-	enc.GasLimit = (*hexutil.Big)(t.GasLimit)
+	enc.GasLimit = hexutil.Uint64(t.GasLimit)
 	enc.Recipient = t.Recipient
 	enc.Amount = (*hexutil.Big)(t.Amount)
 	enc.Payload = t.Payload
@@ -42,7 +42,7 @@ func (t *txdata) UnmarshalJSON(input []byte) error {
 	type txdata struct {
 		AccountNonce *hexutil.Uint64 `json:"nonce"    gencodec:"required"`
 		Price        *hexutil.Big    `json:"gasPrice" gencodec:"required"`
-		GasLimit     *hexutil.Big    `json:"gas"      gencodec:"required"`
+		GasLimit     *hexutil.Uint64 `json:"gas"      gencodec:"required"`
 		Recipient    *common.Address `json:"to"       rlp:"nil"`
 		Amount       *hexutil.Big    `json:"value"    gencodec:"required"`
 		Payload      hexutil.Bytes   `json:"input"    gencodec:"required"`
@@ -66,7 +66,7 @@ func (t *txdata) UnmarshalJSON(input []byte) error {
 	if dec.GasLimit == nil {
 		return errors.New("missing required field 'gas' for txdata")
 	}
-	t.GasLimit = (*big.Int)(dec.GasLimit)
+	t.GasLimit = uint64(*dec.GasLimit)
 	if dec.Recipient != nil {
 		t.Recipient = dec.Recipient
 	}
diff --git a/core/types/receipt.go b/core/types/receipt.go
index bc3c996b4..208d54aaa 100644
--- a/core/types/receipt.go
+++ b/core/types/receipt.go
@@ -20,7 +20,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
@@ -45,46 +44,46 @@ const (
 // Receipt represents the results of a transaction.
 type Receipt struct {
 	// Consensus fields
-	PostState         []byte   `json:"root"`
-	Status            uint     `json:"status"`
-	CumulativeGasUsed *big.Int `json:"cumulativeGasUsed" gencodec:"required"`
-	Bloom             Bloom    `json:"logsBloom"         gencodec:"required"`
-	Logs              []*Log   `json:"logs"              gencodec:"required"`
+	PostState         []byte `json:"root"`
+	Status            uint   `json:"status"`
+	CumulativeGasUsed uint64 `json:"cumulativeGasUsed" gencodec:"required"`
+	Bloom             Bloom  `json:"logsBloom"         gencodec:"required"`
+	Logs              []*Log `json:"logs"              gencodec:"required"`
 
 	// Implementation fields (don't reorder!)
 	TxHash          common.Hash    `json:"transactionHash" gencodec:"required"`
 	ContractAddress common.Address `json:"contractAddress"`
-	GasUsed         *big.Int       `json:"gasUsed" gencodec:"required"`
+	GasUsed         uint64         `json:"gasUsed" gencodec:"required"`
 }
 
 type receiptMarshaling struct {
 	PostState         hexutil.Bytes
 	Status            hexutil.Uint
-	CumulativeGasUsed *hexutil.Big
-	GasUsed           *hexutil.Big
+	CumulativeGasUsed hexutil.Uint64
+	GasUsed           hexutil.Uint64
 }
 
 // receiptRLP is the consensus encoding of a receipt.
 type receiptRLP struct {
 	PostStateOrStatus []byte
-	CumulativeGasUsed *big.Int
+	CumulativeGasUsed uint64
 	Bloom             Bloom
 	Logs              []*Log
 }
 
 type receiptStorageRLP struct {
 	PostStateOrStatus []byte
-	CumulativeGasUsed *big.Int
+	CumulativeGasUsed uint64
 	Bloom             Bloom
 	TxHash            common.Hash
 	ContractAddress   common.Address
 	Logs              []*LogForStorage
-	GasUsed           *big.Int
+	GasUsed           uint64
 }
 
 // NewReceipt creates a barebone transaction receipt, copying the init fields.
-func NewReceipt(root []byte, failed bool, cumulativeGasUsed *big.Int) *Receipt {
-	r := &Receipt{PostState: common.CopyBytes(root), CumulativeGasUsed: new(big.Int).Set(cumulativeGasUsed)}
+func NewReceipt(root []byte, failed bool, cumulativeGasUsed uint64) *Receipt {
+	r := &Receipt{PostState: common.CopyBytes(root), CumulativeGasUsed: cumulativeGasUsed}
 	if failed {
 		r.Status = ReceiptStatusFailed
 	} else {
diff --git a/core/types/transaction.go b/core/types/transaction.go
index ee4140ce4..a7ed211e4 100644
--- a/core/types/transaction.go
+++ b/core/types/transaction.go
@@ -57,7 +57,7 @@ type Transaction struct {
 type txdata struct {
 	AccountNonce uint64          `json:"nonce"    gencodec:"required"`
 	Price        *big.Int        `json:"gasPrice" gencodec:"required"`
-	GasLimit     *big.Int        `json:"gas"      gencodec:"required"`
+	GasLimit     uint64          `json:"gas"      gencodec:"required"`
 	Recipient    *common.Address `json:"to"       rlp:"nil"` // nil means contract creation
 	Amount       *big.Int        `json:"value"    gencodec:"required"`
 	Payload      []byte          `json:"input"    gencodec:"required"`
@@ -74,7 +74,7 @@ type txdata struct {
 type txdataMarshaling struct {
 	AccountNonce hexutil.Uint64
 	Price        *hexutil.Big
-	GasLimit     *hexutil.Big
+	GasLimit     hexutil.Uint64
 	Amount       *hexutil.Big
 	Payload      hexutil.Bytes
 	V            *hexutil.Big
@@ -82,15 +82,15 @@ type txdataMarshaling struct {
 	S            *hexutil.Big
 }
 
-func NewTransaction(nonce uint64, to common.Address, amount, gasLimit, gasPrice *big.Int, data []byte) *Transaction {
+func NewTransaction(nonce uint64, to common.Address, amount *big.Int, gasLimit uint64, gasPrice *big.Int, data []byte) *Transaction {
 	return newTransaction(nonce, &to, amount, gasLimit, gasPrice, data)
 }
 
-func NewContractCreation(nonce uint64, amount, gasLimit, gasPrice *big.Int, data []byte) *Transaction {
+func NewContractCreation(nonce uint64, amount *big.Int, gasLimit uint64, gasPrice *big.Int, data []byte) *Transaction {
 	return newTransaction(nonce, nil, amount, gasLimit, gasPrice, data)
 }
 
-func newTransaction(nonce uint64, to *common.Address, amount, gasLimit, gasPrice *big.Int, data []byte) *Transaction {
+func newTransaction(nonce uint64, to *common.Address, amount *big.Int, gasLimit uint64, gasPrice *big.Int, data []byte) *Transaction {
 	if len(data) > 0 {
 		data = common.CopyBytes(data)
 	}
@@ -99,7 +99,7 @@ func newTransaction(nonce uint64, to *common.Address, amount, gasLimit, gasPrice
 		Recipient:    to,
 		Payload:      data,
 		Amount:       new(big.Int),
-		GasLimit:     new(big.Int),
+		GasLimit:     gasLimit,
 		Price:        new(big.Int),
 		V:            new(big.Int),
 		R:            new(big.Int),
@@ -108,9 +108,6 @@ func newTransaction(nonce uint64, to *common.Address, amount, gasLimit, gasPrice
 	if amount != nil {
 		d.Amount.Set(amount)
 	}
-	if gasLimit != nil {
-		d.GasLimit.Set(gasLimit)
-	}
 	if gasPrice != nil {
 		d.Price.Set(gasPrice)
 	}
@@ -182,7 +179,7 @@ func (tx *Transaction) UnmarshalJSON(input []byte) error {
 }
 
 func (tx *Transaction) Data() []byte       { return common.CopyBytes(tx.data.Payload) }
-func (tx *Transaction) Gas() *big.Int      { return new(big.Int).Set(tx.data.GasLimit) }
+func (tx *Transaction) Gas() uint64        { return tx.data.GasLimit }
 func (tx *Transaction) GasPrice() *big.Int { return new(big.Int).Set(tx.data.Price) }
 func (tx *Transaction) Value() *big.Int    { return new(big.Int).Set(tx.data.Amount) }
 func (tx *Transaction) Nonce() uint64      { return tx.data.AccountNonce }
@@ -227,8 +224,8 @@ func (tx *Transaction) Size() common.StorageSize {
 func (tx *Transaction) AsMessage(s Signer) (Message, error) {
 	msg := Message{
 		nonce:      tx.data.AccountNonce,
-		price:      new(big.Int).Set(tx.data.Price),
-		gasLimit:   new(big.Int).Set(tx.data.GasLimit),
+		gasLimit:   tx.data.GasLimit,
+		gasPrice:   new(big.Int).Set(tx.data.Price),
 		to:         tx.data.Recipient,
 		amount:     tx.data.Amount,
 		data:       tx.data.Payload,
@@ -254,7 +251,7 @@ func (tx *Transaction) WithSignature(signer Signer, sig []byte) (*Transaction, e
 
 // Cost returns amount + gasprice * gaslimit.
 func (tx *Transaction) Cost() *big.Int {
-	total := new(big.Int).Mul(tx.data.Price, tx.data.GasLimit)
+	total := new(big.Int).Mul(tx.data.Price, new(big.Int).SetUint64(tx.data.GasLimit))
 	total.Add(total, tx.data.Amount)
 	return total
 }
@@ -440,22 +437,24 @@ func (t *TransactionsByPriceAndNonce) Pop() {
 //
 // NOTE: In a future PR this will be removed.
 type Message struct {
-	to                      *common.Address
-	from                    common.Address
-	nonce                   uint64
-	amount, price, gasLimit *big.Int
-	data                    []byte
-	checkNonce              bool
+	to         *common.Address
+	from       common.Address
+	nonce      uint64
+	amount     *big.Int
+	gasLimit   uint64
+	gasPrice   *big.Int
+	data       []byte
+	checkNonce bool
 }
 
-func NewMessage(from common.Address, to *common.Address, nonce uint64, amount, gasLimit, price *big.Int, data []byte, checkNonce bool) Message {
+func NewMessage(from common.Address, to *common.Address, nonce uint64, amount *big.Int, gasLimit uint64, gasPrice *big.Int, data []byte, checkNonce bool) Message {
 	return Message{
 		from:       from,
 		to:         to,
 		nonce:      nonce,
 		amount:     amount,
-		price:      price,
 		gasLimit:   gasLimit,
+		gasPrice:   gasPrice,
 		data:       data,
 		checkNonce: checkNonce,
 	}
@@ -463,9 +462,9 @@ func NewMessage(from common.Address, to *common.Address, nonce uint64, amount, g
 
 func (m Message) From() common.Address { return m.from }
 func (m Message) To() *common.Address  { return m.to }
-func (m Message) GasPrice() *big.Int   { return m.price }
+func (m Message) GasPrice() *big.Int   { return m.gasPrice }
 func (m Message) Value() *big.Int      { return m.amount }
-func (m Message) Gas() *big.Int        { return m.gasLimit }
+func (m Message) Gas() uint64          { return m.gasLimit }
 func (m Message) Nonce() uint64        { return m.nonce }
 func (m Message) Data() []byte         { return m.data }
 func (m Message) CheckNonce() bool     { return m.checkNonce }
diff --git a/core/types/transaction_signing_test.go b/core/types/transaction_signing_test.go
index 7f799fb10..689fc38a9 100644
--- a/core/types/transaction_signing_test.go
+++ b/core/types/transaction_signing_test.go
@@ -30,7 +30,7 @@ func TestEIP155Signing(t *testing.T) {
 	addr := crypto.PubkeyToAddress(key.PublicKey)
 
 	signer := NewEIP155Signer(big.NewInt(18))
-	tx, err := SignTx(NewTransaction(0, addr, new(big.Int), new(big.Int), new(big.Int), nil), signer, key)
+	tx, err := SignTx(NewTransaction(0, addr, new(big.Int), 0, new(big.Int), nil), signer, key)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -49,7 +49,7 @@ func TestEIP155ChainId(t *testing.T) {
 	addr := crypto.PubkeyToAddress(key.PublicKey)
 
 	signer := NewEIP155Signer(big.NewInt(18))
-	tx, err := SignTx(NewTransaction(0, addr, new(big.Int), new(big.Int), new(big.Int), nil), signer, key)
+	tx, err := SignTx(NewTransaction(0, addr, new(big.Int), 0, new(big.Int), nil), signer, key)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -61,7 +61,7 @@ func TestEIP155ChainId(t *testing.T) {
 		t.Error("expected chainId to be", signer.chainId, "got", tx.ChainId())
 	}
 
-	tx = NewTransaction(0, addr, new(big.Int), new(big.Int), new(big.Int), nil)
+	tx = NewTransaction(0, addr, new(big.Int), 0, new(big.Int), nil)
 	tx, err = SignTx(tx, HomesteadSigner{}, key)
 	if err != nil {
 		t.Fatal(err)
@@ -118,7 +118,7 @@ func TestEIP155SigningVitalik(t *testing.T) {
 func TestChainId(t *testing.T) {
 	key, _ := defaultTestKey()
 
-	tx := NewTransaction(0, common.Address{}, new(big.Int), new(big.Int), new(big.Int), nil)
+	tx := NewTransaction(0, common.Address{}, new(big.Int), 0, new(big.Int), nil)
 
 	var err error
 	tx, err = SignTx(tx, NewEIP155Signer(big.NewInt(1)), key)
diff --git a/core/types/transaction_test.go b/core/types/transaction_test.go
index 82d74e3b3..d1861b14c 100644
--- a/core/types/transaction_test.go
+++ b/core/types/transaction_test.go
@@ -34,7 +34,7 @@ var (
 	emptyTx = NewTransaction(
 		0,
 		common.HexToAddress("095e7baea6a6c7c4c2dfeb977efac326af552d87"),
-		big.NewInt(0), big.NewInt(0), big.NewInt(0),
+		big.NewInt(0), 0, big.NewInt(0),
 		nil,
 	)
 
@@ -42,7 +42,7 @@ var (
 		3,
 		common.HexToAddress("b94f5374fce5edbc8e2a8697c15331677e6ebf0b"),
 		big.NewInt(10),
-		big.NewInt(2000),
+		2000,
 		big.NewInt(1),
 		common.FromHex("5544"),
 	).WithSignature(
@@ -139,7 +139,7 @@ func TestTransactionPriceNonceSort(t *testing.T) {
 	for start, key := range keys {
 		addr := crypto.PubkeyToAddress(key.PublicKey)
 		for i := 0; i < 25; i++ {
-			tx, _ := SignTx(NewTransaction(uint64(start+i), common.Address{}, big.NewInt(100), big.NewInt(100), big.NewInt(int64(start+i)), nil), signer, key)
+			tx, _ := SignTx(NewTransaction(uint64(start+i), common.Address{}, big.NewInt(100), 100, big.NewInt(int64(start+i)), nil), signer, key)
 			groups[addr] = append(groups[addr], tx)
 		}
 	}
@@ -204,9 +204,9 @@ func TestTransactionJSON(t *testing.T) {
 		var tx *Transaction
 		switch i % 2 {
 		case 0:
-			tx = NewTransaction(i, common.Address{1}, common.Big0, common.Big1, common.Big2, []byte("abcdef"))
+			tx = NewTransaction(i, common.Address{1}, common.Big0, 1, common.Big2, []byte("abcdef"))
 		case 1:
-			tx = NewContractCreation(i, common.Big0, common.Big1, common.Big2, []byte("abcdef"))
+			tx = NewContractCreation(i, common.Big0, 1, common.Big2, []byte("abcdef"))
 		}
 
 		tx, err := SignTx(tx, signer, key)
diff --git a/core/vm/evm.go b/core/vm/evm.go
index a3f3a97cb..8796a633e 100644
--- a/core/vm/evm.go
+++ b/core/vm/evm.go
@@ -69,7 +69,7 @@ type Context struct {
 
 	// Block information
 	Coinbase    common.Address // Provides information for COINBASE
-	GasLimit    *big.Int       // Provides information for GASLIMIT
+	GasLimit    uint64         // Provides information for GASLIMIT
 	BlockNumber *big.Int       // Provides information for NUMBER
 	Time        *big.Int       // Provides information for TIME
 	Difficulty  *big.Int       // Provides information for DIFFICULTY
diff --git a/core/vm/gas_table.go b/core/vm/gas_table.go
index ff109af57..83adba428 100644
--- a/core/vm/gas_table.go
+++ b/core/vm/gas_table.go
@@ -17,8 +17,6 @@
 package vm
 
 import (
-	"math/big"
-
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/params"
@@ -130,7 +128,7 @@ func gasSStore(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, m
 		// 0 => non 0
 		return params.SstoreSetGas, nil
 	} else if !common.EmptyHash(val) && common.EmptyHash(common.BigToHash(y)) {
-		evm.StateDB.AddRefund(new(big.Int).SetUint64(params.SstoreRefundGas))
+		evm.StateDB.AddRefund(params.SstoreRefundGas)
 
 		return params.SstoreClearGas, nil
 	} else {
@@ -405,7 +403,7 @@ func gasSuicide(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack,
 	}
 
 	if !evm.StateDB.HasSuicided(contract.Address()) {
-		evm.StateDB.AddRefund(new(big.Int).SetUint64(params.SuicideRefundGas))
+		evm.StateDB.AddRefund(params.SuicideRefundGas)
 	}
 	return gas, nil
 }
diff --git a/core/vm/instructions.go b/core/vm/instructions.go
index 1d1585fca..766172501 100644
--- a/core/vm/instructions.go
+++ b/core/vm/instructions.go
@@ -472,7 +472,7 @@ func opDifficulty(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stac
 }
 
 func opGasLimit(pc *uint64, evm *EVM, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(math.U256(new(big.Int).Set(evm.GasLimit)))
+	stack.push(math.U256(new(big.Int).SetUint64(evm.GasLimit)))
 	return nil, nil
 }
 
diff --git a/core/vm/interface.go b/core/vm/interface.go
index c0c52732b..1ef91cf1d 100644
--- a/core/vm/interface.go
+++ b/core/vm/interface.go
@@ -39,8 +39,8 @@ type StateDB interface {
 	SetCode(common.Address, []byte)
 	GetCodeSize(common.Address) int
 
-	AddRefund(*big.Int)
-	GetRefund() *big.Int
+	AddRefund(uint64)
+	GetRefund() uint64
 
 	GetState(common.Address, common.Hash) common.Hash
 	SetState(common.Address, common.Hash, common.Hash)
diff --git a/core/vm/noop.go b/core/vm/noop.go
index 2a04a9565..b71ead0d7 100644
--- a/core/vm/noop.go
+++ b/core/vm/noop.go
@@ -55,8 +55,8 @@ func (NoopStateDB) GetCodeHash(common.Address) common.Hash
 func (NoopStateDB) GetCode(common.Address) []byte                                      { return nil }
 func (NoopStateDB) SetCode(common.Address, []byte)                                     {}
 func (NoopStateDB) GetCodeSize(common.Address) int                                     { return 0 }
-func (NoopStateDB) AddRefund(*big.Int)                                                 {}
-func (NoopStateDB) GetRefund() *big.Int                                                { return nil }
+func (NoopStateDB) AddRefund(uint64)                                                   {}
+func (NoopStateDB) GetRefund() uint64                                                  { return 0 }
 func (NoopStateDB) GetState(common.Address, common.Hash) common.Hash                   { return common.Hash{} }
 func (NoopStateDB) SetState(common.Address, common.Hash, common.Hash)                  {}
 func (NoopStateDB) Suicide(common.Address) bool                                        { return false }
diff --git a/core/vm/runtime/env.go b/core/vm/runtime/env.go
index 818da1be2..31c9b9cf9 100644
--- a/core/vm/runtime/env.go
+++ b/core/vm/runtime/env.go
@@ -17,8 +17,6 @@
 package runtime
 
 import (
-	"math/big"
-
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/vm"
@@ -35,7 +33,7 @@ func NewEnv(cfg *Config) *vm.EVM {
 		BlockNumber: cfg.BlockNumber,
 		Time:        cfg.Time,
 		Difficulty:  cfg.Difficulty,
-		GasLimit:    new(big.Int).SetUint64(cfg.GasLimit),
+		GasLimit:    cfg.GasLimit,
 		GasPrice:    cfg.GasPrice,
 	}
 
diff --git a/eth/bind.go b/eth/bind.go
index d09977dbc..769a6c741 100644
--- a/eth/bind.go
+++ b/eth/bind.go
@@ -83,9 +83,7 @@ func toCallArgs(msg ethereum.CallMsg) ethapi.CallArgs {
 		To:   msg.To,
 		From: msg.From,
 		Data: msg.Data,
-	}
-	if msg.Gas != nil {
-		args.Gas = hexutil.Big(*msg.Gas)
+		Gas:  hexutil.Uint64(msg.Gas),
 	}
 	if msg.GasPrice != nil {
 		args.GasPrice = hexutil.Big(*msg.GasPrice)
@@ -124,9 +122,9 @@ func (b *ContractBackend) SuggestGasPrice(ctx context.Context) (*big.Int, error)
 // the backend blockchain. There is no guarantee that this is the true gas limit
 // requirement as other transactions may be added or removed by miners, but it
 // should provide a basis for setting a reasonable default.
-func (b *ContractBackend) EstimateGas(ctx context.Context, msg ethereum.CallMsg) (*big.Int, error) {
-	out, err := b.bcapi.EstimateGas(ctx, toCallArgs(msg))
-	return out.ToInt(), err
+func (b *ContractBackend) EstimateGas(ctx context.Context, msg ethereum.CallMsg) (uint64, error) {
+	gas, err := b.bcapi.EstimateGas(ctx, toCallArgs(msg))
+	return uint64(gas), err
 }
 
 // SendTransaction implements bind.ContractTransactor injects the transaction
diff --git a/eth/downloader/downloader_test.go b/eth/downloader/downloader_test.go
index e14264944..ad5a62c48 100644
--- a/eth/downloader/downloader_test.go
+++ b/eth/downloader/downloader_test.go
@@ -118,7 +118,7 @@ func (dl *downloadTester) makeChain(n int, seed byte, parent *types.Block, paren
 		// If the block number is multiple of 3, send a bonus transaction to the miner
 		if parent == dl.genesis && i%3 == 0 {
 			signer := types.MakeSigner(params.TestChainConfig, block.Number())
-			tx, err := types.SignTx(types.NewTransaction(block.TxNonce(testAddress), common.Address{seed}, big.NewInt(1000), new(big.Int).SetUint64(params.TxGas), nil, nil), signer, testKey)
+			tx, err := types.SignTx(types.NewTransaction(block.TxNonce(testAddress), common.Address{seed}, big.NewInt(1000), params.TxGas, nil, nil), signer, testKey)
 			if err != nil {
 				panic(err)
 			}
diff --git a/eth/fetcher/fetcher_test.go b/eth/fetcher/fetcher_test.go
index e6a639417..9d53b98b6 100644
--- a/eth/fetcher/fetcher_test.go
+++ b/eth/fetcher/fetcher_test.go
@@ -52,7 +52,7 @@ func makeChain(n int, seed byte, parent *types.Block) ([]common.Hash, map[common
 		// If the block number is multiple of 3, send a bonus transaction to the miner
 		if parent == genesis && i%3 == 0 {
 			signer := types.MakeSigner(params.TestChainConfig, block.Number())
-			tx, err := types.SignTx(types.NewTransaction(block.TxNonce(testAddress), common.Address{seed}, big.NewInt(1000), new(big.Int).SetUint64(params.TxGas), nil, nil), signer, testKey)
+			tx, err := types.SignTx(types.NewTransaction(block.TxNonce(testAddress), common.Address{seed}, big.NewInt(1000), params.TxGas, nil, nil), signer, testKey)
 			if err != nil {
 				panic(err)
 			}
diff --git a/eth/filters/filter_system_test.go b/eth/filters/filter_system_test.go
index a5025db3d..dd6d4433d 100644
--- a/eth/filters/filter_system_test.go
+++ b/eth/filters/filter_system_test.go
@@ -195,11 +195,11 @@ func TestPendingTxFilter(t *testing.T) {
 		api        = NewPublicFilterAPI(backend, false)
 
 		transactions = []*types.Transaction{
-			types.NewTransaction(0, common.HexToAddress("0xb794f5ea0ba39494ce83a213fffba74279579268"), new(big.Int), new(big.Int), new(big.Int), nil),
-			types.NewTransaction(1, common.HexToAddress("0xb794f5ea0ba39494ce83a213fffba74279579268"), new(big.Int), new(big.Int), new(big.Int), nil),
-			types.NewTransaction(2, common.HexToAddress("0xb794f5ea0ba39494ce83a213fffba74279579268"), new(big.Int), new(big.Int), new(big.Int), nil),
-			types.NewTransaction(3, common.HexToAddress("0xb794f5ea0ba39494ce83a213fffba74279579268"), new(big.Int), new(big.Int), new(big.Int), nil),
-			types.NewTransaction(4, common.HexToAddress("0xb794f5ea0ba39494ce83a213fffba74279579268"), new(big.Int), new(big.Int), new(big.Int), nil),
+			types.NewTransaction(0, common.HexToAddress("0xb794f5ea0ba39494ce83a213fffba74279579268"), new(big.Int), 0, new(big.Int), nil),
+			types.NewTransaction(1, common.HexToAddress("0xb794f5ea0ba39494ce83a213fffba74279579268"), new(big.Int), 0, new(big.Int), nil),
+			types.NewTransaction(2, common.HexToAddress("0xb794f5ea0ba39494ce83a213fffba74279579268"), new(big.Int), 0, new(big.Int), nil),
+			types.NewTransaction(3, common.HexToAddress("0xb794f5ea0ba39494ce83a213fffba74279579268"), new(big.Int), 0, new(big.Int), nil),
+			types.NewTransaction(4, common.HexToAddress("0xb794f5ea0ba39494ce83a213fffba74279579268"), new(big.Int), 0, new(big.Int), nil),
 		}
 
 		hashes []common.Hash
diff --git a/eth/filters/filter_test.go b/eth/filters/filter_test.go
index 729d0afc8..0018142c4 100644
--- a/eth/filters/filter_test.go
+++ b/eth/filters/filter_test.go
@@ -34,7 +34,7 @@ import (
 )
 
 func makeReceipt(addr common.Address) *types.Receipt {
-	receipt := types.NewReceipt(nil, false, new(big.Int))
+	receipt := types.NewReceipt(nil, false, 0)
 	receipt.Logs = []*types.Log{
 		{Address: addr},
 	}
@@ -136,7 +136,7 @@ func TestFilters(t *testing.T) {
 	chain, receipts := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), db, 1000, func(i int, gen *core.BlockGen) {
 		switch i {
 		case 1:
-			receipt := types.NewReceipt(nil, false, new(big.Int))
+			receipt := types.NewReceipt(nil, false, 0)
 			receipt.Logs = []*types.Log{
 				{
 					Address: addr,
@@ -145,7 +145,7 @@ func TestFilters(t *testing.T) {
 			}
 			gen.AddUncheckedReceipt(receipt)
 		case 2:
-			receipt := types.NewReceipt(nil, false, new(big.Int))
+			receipt := types.NewReceipt(nil, false, 0)
 			receipt.Logs = []*types.Log{
 				{
 					Address: addr,
@@ -154,7 +154,7 @@ func TestFilters(t *testing.T) {
 			}
 			gen.AddUncheckedReceipt(receipt)
 		case 998:
-			receipt := types.NewReceipt(nil, false, new(big.Int))
+			receipt := types.NewReceipt(nil, false, 0)
 			receipt.Logs = []*types.Log{
 				{
 					Address: addr,
@@ -163,7 +163,7 @@ func TestFilters(t *testing.T) {
 			}
 			gen.AddUncheckedReceipt(receipt)
 		case 999:
-			receipt := types.NewReceipt(nil, false, new(big.Int))
+			receipt := types.NewReceipt(nil, false, 0)
 			receipt.Logs = []*types.Log{
 				{
 					Address: addr,
diff --git a/eth/handler_test.go b/eth/handler_test.go
index ebbd83c3a..9a02eddfb 100644
--- a/eth/handler_test.go
+++ b/eth/handler_test.go
@@ -37,8 +37,6 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 )
 
-var bigTxGas = new(big.Int).SetUint64(params.TxGas)
-
 // Tests that protocol versions and modes of operations are matched up properly.
 func TestProtocolCompatibility(t *testing.T) {
 	// Define the compatibility chart
@@ -315,13 +313,13 @@ func testGetNodeData(t *testing.T, protocol int) {
 		switch i {
 		case 0:
 			// In block 1, the test bank sends account #1 some ether.
-			tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(10000), bigTxGas, nil, nil), signer, testBankKey)
+			tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(10000), params.TxGas, nil, nil), signer, testBankKey)
 			block.AddTx(tx)
 		case 1:
 			// In block 2, the test bank sends some more ether to account #1.
 			// acc1Addr passes it on to account #2.
-			tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, testBankKey)
-			tx2, _ := types.SignTx(types.NewTransaction(block.TxNonce(acc1Addr), acc2Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, acc1Key)
+			tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, testBankKey)
+			tx2, _ := types.SignTx(types.NewTransaction(block.TxNonce(acc1Addr), acc2Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, acc1Key)
 			block.AddTx(tx1)
 			block.AddTx(tx2)
 		case 2:
@@ -407,13 +405,13 @@ func testGetReceipt(t *testing.T, protocol int) {
 		switch i {
 		case 0:
 			// In block 1, the test bank sends account #1 some ether.
-			tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(10000), bigTxGas, nil, nil), signer, testBankKey)
+			tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(10000), params.TxGas, nil, nil), signer, testBankKey)
 			block.AddTx(tx)
 		case 1:
 			// In block 2, the test bank sends some more ether to account #1.
 			// acc1Addr passes it on to account #2.
-			tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, testBankKey)
-			tx2, _ := types.SignTx(types.NewTransaction(block.TxNonce(acc1Addr), acc2Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, acc1Key)
+			tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBank), acc1Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, testBankKey)
+			tx2, _ := types.SignTx(types.NewTransaction(block.TxNonce(acc1Addr), acc2Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, acc1Key)
 			block.AddTx(tx1)
 			block.AddTx(tx2)
 		case 2:
diff --git a/eth/helper_test.go b/eth/helper_test.go
index bfb003c8b..d44574b86 100644
--- a/eth/helper_test.go
+++ b/eth/helper_test.go
@@ -130,7 +130,7 @@ func (p *testTxPool) SubscribeTxPreEvent(ch chan<- core.TxPreEvent) event.Subscr
 
 // newTestTransaction create a new dummy transaction.
 func newTestTransaction(from *ecdsa.PrivateKey, nonce uint64, datasize int) *types.Transaction {
-	tx := types.NewTransaction(nonce, common.Address{}, big.NewInt(0), big.NewInt(100000), big.NewInt(0), make([]byte, datasize))
+	tx := types.NewTransaction(nonce, common.Address{}, big.NewInt(0), 100000, big.NewInt(0), make([]byte, datasize))
 	tx, _ = types.SignTx(tx, types.HomesteadSigner{}, from)
 	return tx
 }
diff --git a/eth/tracers/tracers_test.go b/eth/tracers/tracers_test.go
index 139280797..bf8120228 100644
--- a/eth/tracers/tracers_test.go
+++ b/eth/tracers/tracers_test.go
@@ -156,7 +156,7 @@ func TestCallTracer(t *testing.T) {
 				BlockNumber: new(big.Int).SetUint64(uint64(test.Context.Number)),
 				Time:        new(big.Int).SetUint64(uint64(test.Context.Time)),
 				Difficulty:  (*big.Int)(test.Context.Difficulty),
-				GasLimit:    new(big.Int).SetUint64(uint64(test.Context.GasLimit)),
+				GasLimit:    uint64(test.Context.GasLimit),
 				GasPrice:    tx.GasPrice(),
 			}
 			db, _ := ethdb.NewMemDatabase()
@@ -174,7 +174,7 @@ func TestCallTracer(t *testing.T) {
 				t.Fatalf("failed to prepare transaction for tracing: %v", err)
 			}
 			st := core.NewStateTransition(evm, msg, new(core.GasPool).AddGas(tx.Gas()))
-			if _, _, _, _, err = st.TransitionDb(); err != nil {
+			if _, _, _, err = st.TransitionDb(); err != nil {
 				t.Fatalf("failed to execute transaction: %v", err)
 			}
 			// Retrieve the trace result and compare against the etalon
diff --git a/ethclient/ethclient.go b/ethclient/ethclient.go
index 7f73ab113..87a912901 100644
--- a/ethclient/ethclient.go
+++ b/ethclient/ethclient.go
@@ -455,13 +455,13 @@ func (ec *Client) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
 // the current pending state of the backend blockchain. There is no guarantee that this is
 // the true gas limit requirement as other transactions may be added or removed by miners,
 // but it should provide a basis for setting a reasonable default.
-func (ec *Client) EstimateGas(ctx context.Context, msg ethereum.CallMsg) (*big.Int, error) {
-	var hex hexutil.Big
+func (ec *Client) EstimateGas(ctx context.Context, msg ethereum.CallMsg) (uint64, error) {
+	var hex hexutil.Uint64
 	err := ec.c.CallContext(ctx, &hex, "eth_estimateGas", toCallArg(msg))
 	if err != nil {
-		return nil, err
+		return 0, err
 	}
-	return (*big.Int)(&hex), nil
+	return uint64(hex), nil
 }
 
 // SendTransaction injects a signed transaction into the pending pool for execution.
@@ -487,8 +487,8 @@ func toCallArg(msg ethereum.CallMsg) interface{} {
 	if msg.Value != nil {
 		arg["value"] = (*hexutil.Big)(msg.Value)
 	}
-	if msg.Gas != nil {
-		arg["gas"] = (*hexutil.Big)(msg.Gas)
+	if msg.Gas != 0 {
+		arg["gas"] = hexutil.Uint64(msg.Gas)
 	}
 	if msg.GasPrice != nil {
 		arg["gasPrice"] = (*hexutil.Big)(msg.GasPrice)
diff --git a/ethstats/ethstats.go b/ethstats/ethstats.go
index 1e27a1e63..8204750be 100644
--- a/ethstats/ethstats.go
+++ b/ethstats/ethstats.go
@@ -473,8 +473,8 @@ type blockStats struct {
 	ParentHash common.Hash    `json:"parentHash"`
 	Timestamp  *big.Int       `json:"timestamp"`
 	Miner      common.Address `json:"miner"`
-	GasUsed    *big.Int       `json:"gasUsed"`
-	GasLimit   *big.Int       `json:"gasLimit"`
+	GasUsed    uint64         `json:"gasUsed"`
+	GasLimit   uint64         `json:"gasLimit"`
 	Diff       string         `json:"difficulty"`
 	TotalDiff  string         `json:"totalDifficulty"`
 	Txs        []txStats      `json:"transactions"`
@@ -559,8 +559,8 @@ func (s *Service) assembleBlockStats(block *types.Block) *blockStats {
 		ParentHash: header.ParentHash,
 		Timestamp:  header.Time,
 		Miner:      author,
-		GasUsed:    new(big.Int).Set(header.GasUsed),
-		GasLimit:   new(big.Int).Set(header.GasLimit),
+		GasUsed:    header.GasUsed,
+		GasLimit:   header.GasLimit,
 		Diff:       header.Difficulty.String(),
 		TotalDiff:  td.String(),
 		Txs:        txs,
diff --git a/interfaces.go b/interfaces.go
index 67f236ef7..1ae1eba48 100644
--- a/interfaces.go
+++ b/interfaces.go
@@ -115,7 +115,7 @@ type ChainSyncReader interface {
 type CallMsg struct {
 	From     common.Address  // the sender of the 'transaction'
 	To       *common.Address // the destination contract (nil for contract creation)
-	Gas      *big.Int        // if nil, the call executes with near-infinite gas
+	Gas      uint64          // if 0, the call executes with near-infinite gas
 	GasPrice *big.Int        // wei <-> gas exchange ratio
 	Value    *big.Int        // amount of wei sent along with the call
 	Data     []byte          // input data, usually an ABI-encoded contract method invocation
@@ -200,7 +200,7 @@ type PendingContractCaller interface {
 // true gas limit requirement as other transactions may be added or removed by miners, but
 // it should provide a basis for setting a reasonable default.
 type GasEstimator interface {
-	EstimateGas(ctx context.Context, call CallMsg) (usedGas *big.Int, err error)
+	EstimateGas(ctx context.Context, call CallMsg) (uint64, error)
 }
 
 // A PendingStateEventer provides access to real time notifications about changes to the
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index d07b2e693..55bd5aa1b 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -45,7 +45,6 @@ import (
 )
 
 const (
-	defaultGas      = 90000
 	defaultGasPrice = 50 * params.Shannon
 )
 
@@ -575,18 +574,18 @@ func (s *PublicBlockChainAPI) GetStorageAt(ctx context.Context, address common.A
 type CallArgs struct {
 	From     common.Address  `json:"from"`
 	To       *common.Address `json:"to"`
-	Gas      hexutil.Big     `json:"gas"`
+	Gas      hexutil.Uint64  `json:"gas"`
 	GasPrice hexutil.Big     `json:"gasPrice"`
 	Value    hexutil.Big     `json:"value"`
 	Data     hexutil.Bytes   `json:"data"`
 }
 
-func (s *PublicBlockChainAPI) doCall(ctx context.Context, args CallArgs, blockNr rpc.BlockNumber, vmCfg vm.Config) ([]byte, *big.Int, bool, error) {
+func (s *PublicBlockChainAPI) doCall(ctx context.Context, args CallArgs, blockNr rpc.BlockNumber, vmCfg vm.Config) ([]byte, uint64, bool, error) {
 	defer func(start time.Time) { log.Debug("Executing EVM call finished", "runtime", time.Since(start)) }(time.Now())
 
 	state, header, err := s.b.StateAndHeaderByNumber(ctx, blockNr)
 	if state == nil || err != nil {
-		return nil, common.Big0, false, err
+		return nil, 0, false, err
 	}
 	// Set sender address or use a default if none specified
 	addr := args.From
@@ -598,9 +597,9 @@ func (s *PublicBlockChainAPI) doCall(ctx context.Context, args CallArgs, blockNr
 		}
 	}
 	// Set default gas & gas price if none were set
-	gas, gasPrice := args.Gas.ToInt(), args.GasPrice.ToInt()
-	if gas.Sign() == 0 {
-		gas = big.NewInt(50000000)
+	gas, gasPrice := uint64(args.Gas), args.GasPrice.ToInt()
+	if gas == 0 {
+		gas = 50000000
 	}
 	if gasPrice.Sign() == 0 {
 		gasPrice = new(big.Int).SetUint64(defaultGasPrice)
@@ -624,7 +623,7 @@ func (s *PublicBlockChainAPI) doCall(ctx context.Context, args CallArgs, blockNr
 	// Get a new instance of the EVM.
 	evm, vmError, err := s.b.GetEVM(ctx, msg, state, header, vmCfg)
 	if err != nil {
-		return nil, common.Big0, false, err
+		return nil, 0, false, err
 	}
 	// Wait for the context to be done and cancel the evm. Even if the
 	// EVM has finished, cancelling may be done (repeatedly)
@@ -635,10 +634,10 @@ func (s *PublicBlockChainAPI) doCall(ctx context.Context, args CallArgs, blockNr
 
 	// Setup the gas pool (also for unmetered requests)
 	// and apply the message.
-	gp := new(core.GasPool).AddGas(math.MaxBig256)
+	gp := new(core.GasPool).AddGas(math.MaxUint64)
 	res, gas, failed, err := core.ApplyMessage(evm, msg, gp)
 	if err := vmError(); err != nil {
-		return nil, common.Big0, false, err
+		return nil, 0, false, err
 	}
 	return res, gas, failed, err
 }
@@ -652,28 +651,29 @@ func (s *PublicBlockChainAPI) Call(ctx context.Context, args CallArgs, blockNr r
 
 // EstimateGas returns an estimate of the amount of gas needed to execute the
 // given transaction against the current pending block.
-func (s *PublicBlockChainAPI) EstimateGas(ctx context.Context, args CallArgs) (*hexutil.Big, error) {
-	// Determine the lowest and highest possible gas limits to binary search in between
+func (s *PublicBlockChainAPI) EstimateGas(ctx context.Context, args CallArgs) (hexutil.Uint64, error) {
+	// Binary search the gas requirement, as it may be higher than the amount used
 	var (
 		lo  uint64 = params.TxGas - 1
 		hi  uint64
 		cap uint64
 	)
-	if (*big.Int)(&args.Gas).Uint64() >= params.TxGas {
-		hi = (*big.Int)(&args.Gas).Uint64()
+	if uint64(args.Gas) >= params.TxGas {
+		hi = uint64(args.Gas)
 	} else {
 		// Retrieve the current pending block to act as the gas ceiling
 		block, err := s.b.BlockByNumber(ctx, rpc.PendingBlockNumber)
 		if err != nil {
-			return nil, err
+			return 0, err
 		}
-		hi = block.GasLimit().Uint64()
+		hi = block.GasLimit()
 	}
 	cap = hi
 
 	// Create a helper to check if a gas allowance results in an executable transaction
 	executable := func(gas uint64) bool {
-		(*big.Int)(&args.Gas).SetUint64(gas)
+		args.Gas = hexutil.Uint64(gas)
+
 		_, _, failed, err := s.doCall(ctx, args, rpc.PendingBlockNumber, vm.Config{})
 		if err != nil || failed {
 			return false
@@ -692,17 +692,17 @@ func (s *PublicBlockChainAPI) EstimateGas(ctx context.Context, args CallArgs) (*
 	// Reject the transaction as invalid if it still fails at the highest allowance
 	if hi == cap {
 		if !executable(hi) {
-			return nil, fmt.Errorf("gas required exceeds allowance or always failing transaction")
+			return 0, fmt.Errorf("gas required exceeds allowance or always failing transaction")
 		}
 	}
-	return (*hexutil.Big)(new(big.Int).SetUint64(hi)), nil
+	return hexutil.Uint64(hi), nil
 }
 
 // ExecutionResult groups all structured logs emitted by the EVM
 // while replaying a transaction in debug mode as well as transaction
 // execution status, the amount of gas used and the return value
 type ExecutionResult struct {
-	Gas         *big.Int       `json:"gas"`
+	Gas         uint64         `json:"gas"`
 	Failed      bool           `json:"failed"`
 	ReturnValue string         `json:"returnValue"`
 	StructLogs  []StructLogRes `json:"structLogs"`
@@ -778,8 +778,8 @@ func (s *PublicBlockChainAPI) rpcOutputBlock(b *types.Block, inclTx bool, fullTx
 		"totalDifficulty":  (*hexutil.Big)(s.b.GetTd(b.Hash())),
 		"extraData":        hexutil.Bytes(head.Extra),
 		"size":             hexutil.Uint64(uint64(b.Size().Int64())),
-		"gasLimit":         (*hexutil.Big)(head.GasLimit),
-		"gasUsed":          (*hexutil.Big)(head.GasUsed),
+		"gasLimit":         hexutil.Uint64(head.GasLimit),
+		"gasUsed":          hexutil.Uint64(head.GasUsed),
 		"timestamp":        (*hexutil.Big)(head.Time),
 		"transactionsRoot": head.TxHash,
 		"receiptsRoot":     head.ReceiptHash,
@@ -822,7 +822,7 @@ type RPCTransaction struct {
 	BlockHash        common.Hash     `json:"blockHash"`
 	BlockNumber      *hexutil.Big    `json:"blockNumber"`
 	From             common.Address  `json:"from"`
-	Gas              *hexutil.Big    `json:"gas"`
+	Gas              hexutil.Uint64  `json:"gas"`
 	GasPrice         *hexutil.Big    `json:"gasPrice"`
 	Hash             common.Hash     `json:"hash"`
 	Input            hexutil.Bytes   `json:"input"`
@@ -847,7 +847,7 @@ func newRPCTransaction(tx *types.Transaction, blockHash common.Hash, blockNumber
 
 	result := &RPCTransaction{
 		From:     from,
-		Gas:      (*hexutil.Big)(tx.Gas()),
+		Gas:      hexutil.Uint64(tx.Gas()),
 		GasPrice: (*hexutil.Big)(tx.GasPrice()),
 		Hash:     tx.Hash(),
 		Input:    hexutil.Bytes(tx.Data()),
@@ -1024,8 +1024,8 @@ func (s *PublicTransactionPoolAPI) GetTransactionReceipt(hash common.Hash) (map[
 		"transactionIndex":  hexutil.Uint64(index),
 		"from":              from,
 		"to":                tx.To(),
-		"gasUsed":           (*hexutil.Big)(receipt.GasUsed),
-		"cumulativeGasUsed": (*hexutil.Big)(receipt.CumulativeGasUsed),
+		"gasUsed":           hexutil.Uint64(receipt.GasUsed),
+		"cumulativeGasUsed": hexutil.Uint64(receipt.CumulativeGasUsed),
 		"contractAddress":   nil,
 		"logs":              receipt.Logs,
 		"logsBloom":         receipt.Bloom,
@@ -1068,7 +1068,7 @@ func (s *PublicTransactionPoolAPI) sign(addr common.Address, tx *types.Transacti
 type SendTxArgs struct {
 	From     common.Address  `json:"from"`
 	To       *common.Address `json:"to"`
-	Gas      *hexutil.Big    `json:"gas"`
+	Gas      *hexutil.Uint64 `json:"gas"`
 	GasPrice *hexutil.Big    `json:"gasPrice"`
 	Value    *hexutil.Big    `json:"value"`
 	Nonce    *hexutil.Uint64 `json:"nonce"`
@@ -1081,7 +1081,8 @@ type SendTxArgs struct {
 // setDefaults is a helper function that fills in default values for unspecified tx fields.
 func (args *SendTxArgs) setDefaults(ctx context.Context, b Backend) error {
 	if args.Gas == nil {
-		args.Gas = (*hexutil.Big)(big.NewInt(defaultGas))
+		args.Gas = new(hexutil.Uint64)
+		*(*uint64)(args.Gas) = 90000
 	}
 	if args.GasPrice == nil {
 		price, err := b.SuggestPrice(ctx)
@@ -1114,9 +1115,9 @@ func (args *SendTxArgs) toTransaction() *types.Transaction {
 		input = *args.Input
 	}
 	if args.To == nil {
-		return types.NewContractCreation(uint64(*args.Nonce), (*big.Int)(args.Value), (*big.Int)(args.Gas), (*big.Int)(args.GasPrice), input)
+		return types.NewContractCreation(uint64(*args.Nonce), (*big.Int)(args.Value), uint64(*args.Gas), (*big.Int)(args.GasPrice), input)
 	}
-	return types.NewTransaction(uint64(*args.Nonce), *args.To, (*big.Int)(args.Value), (*big.Int)(args.Gas), (*big.Int)(args.GasPrice), input)
+	return types.NewTransaction(uint64(*args.Nonce), *args.To, (*big.Int)(args.Value), uint64(*args.Gas), (*big.Int)(args.GasPrice), input)
 }
 
 // submitTransaction is a helper function that submits tx to txPool and logs a message.
@@ -1264,7 +1265,7 @@ func (s *PublicTransactionPoolAPI) PendingTransactions() ([]*RPCTransaction, err
 
 // Resend accepts an existing transaction and a new gas price and limit. It will remove
 // the given transaction from the pool and reinsert it with the new gas price and limit.
-func (s *PublicTransactionPoolAPI) Resend(ctx context.Context, sendArgs SendTxArgs, gasPrice, gasLimit *hexutil.Big) (common.Hash, error) {
+func (s *PublicTransactionPoolAPI) Resend(ctx context.Context, sendArgs SendTxArgs, gasPrice *hexutil.Big, gasLimit *hexutil.Uint64) (common.Hash, error) {
 	if sendArgs.Nonce == nil {
 		return common.Hash{}, fmt.Errorf("missing transaction nonce in transaction spec")
 	}
diff --git a/internal/ethapi/backend.go b/internal/ethapi/backend.go
index 368fa4872..af95d7906 100644
--- a/internal/ethapi/backend.go
+++ b/internal/ethapi/backend.go
@@ -37,13 +37,14 @@ import (
 // Backend interface provides the common API services (that are provided by
 // both full and light clients) with access to necessary functions.
 type Backend interface {
-	// general Ethereum API
+	// General Ethereum API
 	Downloader() *downloader.Downloader
 	ProtocolVersion() int
 	SuggestPrice(ctx context.Context) (*big.Int, error)
 	ChainDb() ethdb.Database
 	EventMux() *event.TypeMux
 	AccountManager() *accounts.Manager
+
 	// BlockChain API
 	SetHead(number uint64)
 	HeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Header, error)
diff --git a/les/handler_test.go b/les/handler_test.go
index 6207061cc..7d67af26a 100644
--- a/les/handler_test.go
+++ b/les/handler_test.go
@@ -443,16 +443,16 @@ func TestTransactionStatusLes2(t *testing.T) {
 	signer := types.HomesteadSigner{}
 
 	// test error status by sending an underpriced transaction
-	tx0, _ := types.SignTx(types.NewTransaction(0, acc1Addr, big.NewInt(10000), bigTxGas, nil, nil), signer, testBankKey)
+	tx0, _ := types.SignTx(types.NewTransaction(0, acc1Addr, big.NewInt(10000), params.TxGas, nil, nil), signer, testBankKey)
 	test(tx0, true, txStatus{Status: core.TxStatusUnknown, Error: core.ErrUnderpriced})
 
-	tx1, _ := types.SignTx(types.NewTransaction(0, acc1Addr, big.NewInt(10000), bigTxGas, big.NewInt(100000000000), nil), signer, testBankKey)
+	tx1, _ := types.SignTx(types.NewTransaction(0, acc1Addr, big.NewInt(10000), params.TxGas, big.NewInt(100000000000), nil), signer, testBankKey)
 	test(tx1, false, txStatus{Status: core.TxStatusUnknown}) // query before sending, should be unknown
 	test(tx1, true, txStatus{Status: core.TxStatusPending})  // send valid processable tx, should return pending
 	test(tx1, true, txStatus{Status: core.TxStatusPending})  // adding it again should not return an error
 
-	tx2, _ := types.SignTx(types.NewTransaction(1, acc1Addr, big.NewInt(10000), bigTxGas, big.NewInt(100000000000), nil), signer, testBankKey)
-	tx3, _ := types.SignTx(types.NewTransaction(2, acc1Addr, big.NewInt(10000), bigTxGas, big.NewInt(100000000000), nil), signer, testBankKey)
+	tx2, _ := types.SignTx(types.NewTransaction(1, acc1Addr, big.NewInt(10000), params.TxGas, big.NewInt(100000000000), nil), signer, testBankKey)
+	tx3, _ := types.SignTx(types.NewTransaction(2, acc1Addr, big.NewInt(10000), params.TxGas, big.NewInt(100000000000), nil), signer, testBankKey)
 	// send transactions in the wrong order, tx3 should be queued
 	test(tx3, true, txStatus{Status: core.TxStatusQueued})
 	test(tx2, true, txStatus{Status: core.TxStatusPending})
diff --git a/les/helper_test.go b/les/helper_test.go
index 92a98e27e..b881b41ce 100644
--- a/les/helper_test.go
+++ b/les/helper_test.go
@@ -56,8 +56,6 @@ var (
 	testContractDeployed     = uint64(2)
 
 	testBufLimit = uint64(100)
-
-	bigTxGas = new(big.Int).SetUint64(params.TxGas)
 )
 
 /*
@@ -81,17 +79,17 @@ func testChainGen(i int, block *core.BlockGen) {
 	switch i {
 	case 0:
 		// In block 1, the test bank sends account #1 some ether.
-		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(10000), bigTxGas, nil, nil), signer, testBankKey)
+		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(10000), params.TxGas, nil, nil), signer, testBankKey)
 		block.AddTx(tx)
 	case 1:
 		// In block 2, the test bank sends some more ether to account #1.
 		// acc1Addr passes it on to account #2.
 		// acc1Addr creates a test contract.
-		tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, testBankKey)
+		tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, testBankKey)
 		nonce := block.TxNonce(acc1Addr)
-		tx2, _ := types.SignTx(types.NewTransaction(nonce, acc2Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, acc1Key)
+		tx2, _ := types.SignTx(types.NewTransaction(nonce, acc2Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, acc1Key)
 		nonce++
-		tx3, _ := types.SignTx(types.NewContractCreation(nonce, big.NewInt(0), big.NewInt(200000), big.NewInt(0), testContractCode), signer, acc1Key)
+		tx3, _ := types.SignTx(types.NewContractCreation(nonce, big.NewInt(0), 200000, big.NewInt(0), testContractCode), signer, acc1Key)
 		testContractAddr = crypto.CreateAddress(acc1Addr, nonce)
 		block.AddTx(tx1)
 		block.AddTx(tx2)
@@ -101,7 +99,7 @@ func testChainGen(i int, block *core.BlockGen) {
 		block.SetCoinbase(acc2Addr)
 		block.SetExtra([]byte("yeehaw"))
 		data := common.Hex2Bytes("C16431B900000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000001")
-		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), testContractAddr, big.NewInt(0), big.NewInt(100000), nil, data), signer, testBankKey)
+		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), testContractAddr, big.NewInt(0), 100000, nil, data), signer, testBankKey)
 		block.AddTx(tx)
 	case 3:
 		// Block 4 includes blocks 2 and 3 as uncle headers (with modified extra data).
@@ -112,7 +110,7 @@ func testChainGen(i int, block *core.BlockGen) {
 		b3.Extra = []byte("foo")
 		block.AddUncle(b3)
 		data := common.Hex2Bytes("C16431B900000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000002")
-		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), testContractAddr, big.NewInt(0), big.NewInt(100000), nil, data), signer, testBankKey)
+		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), testContractAddr, big.NewInt(0), 100000, nil, data), signer, testBankKey)
 		block.AddTx(tx)
 	}
 }
diff --git a/les/odr_test.go b/les/odr_test.go
index 865f5d83e..cf609be88 100644
--- a/les/odr_test.go
+++ b/les/odr_test.go
@@ -129,13 +129,13 @@ func odrContractCall(ctx context.Context, db ethdb.Database, config *params.Chai
 				from := statedb.GetOrNewStateObject(testBankAddress)
 				from.SetBalance(math.MaxBig256)
 
-				msg := callmsg{types.NewMessage(from.Address(), &testContractAddr, 0, new(big.Int), big.NewInt(100000), new(big.Int), data, false)}
+				msg := callmsg{types.NewMessage(from.Address(), &testContractAddr, 0, new(big.Int), 100000, new(big.Int), data, false)}
 
 				context := core.NewEVMContext(msg, header, bc, nil)
 				vmenv := vm.NewEVM(context, statedb, config, vm.Config{})
 
 				//vmenv := core.NewEnv(statedb, config, bc, msg, header, vm.Config{})
-				gp := new(core.GasPool).AddGas(math.MaxBig256)
+				gp := new(core.GasPool).AddGas(math.MaxUint64)
 				ret, _, _, _ := core.ApplyMessage(vmenv, msg, gp)
 				res = append(res, ret...)
 			}
@@ -143,10 +143,10 @@ func odrContractCall(ctx context.Context, db ethdb.Database, config *params.Chai
 			header := lc.GetHeaderByHash(bhash)
 			state := light.NewState(ctx, header, lc.Odr())
 			state.SetBalance(testBankAddress, math.MaxBig256)
-			msg := callmsg{types.NewMessage(testBankAddress, &testContractAddr, 0, new(big.Int), big.NewInt(100000), new(big.Int), data, false)}
+			msg := callmsg{types.NewMessage(testBankAddress, &testContractAddr, 0, new(big.Int), 100000, new(big.Int), data, false)}
 			context := core.NewEVMContext(msg, header, lc, nil)
 			vmenv := vm.NewEVM(context, state, config, vm.Config{})
-			gp := new(core.GasPool).AddGas(math.MaxBig256)
+			gp := new(core.GasPool).AddGas(math.MaxUint64)
 			ret, _, _, _ := core.ApplyMessage(vmenv, msg, gp)
 			if state.Error() == nil {
 				res = append(res, ret...)
diff --git a/light/lightchain.go b/light/lightchain.go
index c5c2dcf46..03c7c1f0d 100644
--- a/light/lightchain.go
+++ b/light/lightchain.go
@@ -169,7 +169,7 @@ func (bc *LightChain) SetHead(head uint64) {
 }
 
 // GasLimit returns the gas limit of the current HEAD block.
-func (self *LightChain) GasLimit() *big.Int {
+func (self *LightChain) GasLimit() uint64 {
 	self.mu.RLock()
 	defer self.mu.RUnlock()
 
diff --git a/light/odr_test.go b/light/odr_test.go
index c0eb409f9..e3d07518a 100644
--- a/light/odr_test.go
+++ b/light/odr_test.go
@@ -50,8 +50,6 @@ var (
 
 	testContractCode = common.Hex2Bytes("606060405260cc8060106000396000f360606040526000357c01000000000000000000000000000000000000000000000000000000009004806360cd2685146041578063c16431b914606b57603f565b005b6055600480803590602001909190505060a9565b6040518082815260200191505060405180910390f35b60886004808035906020019091908035906020019091905050608a565b005b80600060005083606481101560025790900160005b50819055505b5050565b6000600060005082606481101560025790900160005b5054905060c7565b91905056")
 	testContractAddr common.Address
-
-	bigTxGas = new(big.Int).SetUint64(params.TxGas)
 )
 
 type testOdr struct {
@@ -178,10 +176,10 @@ func odrContractCall(ctx context.Context, db ethdb.Database, bc *core.BlockChain
 
 		// Perform read-only call.
 		st.SetBalance(testBankAddress, math.MaxBig256)
-		msg := callmsg{types.NewMessage(testBankAddress, &testContractAddr, 0, new(big.Int), big.NewInt(1000000), new(big.Int), data, false)}
+		msg := callmsg{types.NewMessage(testBankAddress, &testContractAddr, 0, new(big.Int), 1000000, new(big.Int), data, false)}
 		context := core.NewEVMContext(msg, header, chain, nil)
 		vmenv := vm.NewEVM(context, st, config, vm.Config{})
-		gp := new(core.GasPool).AddGas(math.MaxBig256)
+		gp := new(core.GasPool).AddGas(math.MaxUint64)
 		ret, _, _, _ := core.ApplyMessage(vmenv, msg, gp)
 		res = append(res, ret...)
 		if st.Error() != nil {
@@ -196,17 +194,17 @@ func testChainGen(i int, block *core.BlockGen) {
 	switch i {
 	case 0:
 		// In block 1, the test bank sends account #1 some ether.
-		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(10000), bigTxGas, nil, nil), signer, testBankKey)
+		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(10000), params.TxGas, nil, nil), signer, testBankKey)
 		block.AddTx(tx)
 	case 1:
 		// In block 2, the test bank sends some more ether to account #1.
 		// acc1Addr passes it on to account #2.
 		// acc1Addr creates a test contract.
-		tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, testBankKey)
+		tx1, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), acc1Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, testBankKey)
 		nonce := block.TxNonce(acc1Addr)
-		tx2, _ := types.SignTx(types.NewTransaction(nonce, acc2Addr, big.NewInt(1000), bigTxGas, nil, nil), signer, acc1Key)
+		tx2, _ := types.SignTx(types.NewTransaction(nonce, acc2Addr, big.NewInt(1000), params.TxGas, nil, nil), signer, acc1Key)
 		nonce++
-		tx3, _ := types.SignTx(types.NewContractCreation(nonce, big.NewInt(0), big.NewInt(1000000), big.NewInt(0), testContractCode), signer, acc1Key)
+		tx3, _ := types.SignTx(types.NewContractCreation(nonce, big.NewInt(0), 1000000, big.NewInt(0), testContractCode), signer, acc1Key)
 		testContractAddr = crypto.CreateAddress(acc1Addr, nonce)
 		block.AddTx(tx1)
 		block.AddTx(tx2)
@@ -216,7 +214,7 @@ func testChainGen(i int, block *core.BlockGen) {
 		block.SetCoinbase(acc2Addr)
 		block.SetExtra([]byte("yeehaw"))
 		data := common.Hex2Bytes("C16431B900000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000001")
-		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), testContractAddr, big.NewInt(0), big.NewInt(100000), nil, data), signer, testBankKey)
+		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), testContractAddr, big.NewInt(0), 100000, nil, data), signer, testBankKey)
 		block.AddTx(tx)
 	case 3:
 		// Block 4 includes blocks 2 and 3 as uncle headers (with modified extra data).
@@ -227,7 +225,7 @@ func testChainGen(i int, block *core.BlockGen) {
 		b3.Extra = []byte("foo")
 		block.AddUncle(b3)
 		data := common.Hex2Bytes("C16431B900000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000002")
-		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), testContractAddr, big.NewInt(0), big.NewInt(100000), nil, data), signer, testBankKey)
+		tx, _ := types.SignTx(types.NewTransaction(block.TxNonce(testBankAddress), testContractAddr, big.NewInt(0), 100000, nil, data), signer, testBankKey)
 		block.AddTx(tx)
 	}
 }
diff --git a/light/txpool.go b/light/txpool.go
index bd215b992..ca41490bd 100644
--- a/light/txpool.go
+++ b/light/txpool.go
@@ -358,7 +358,7 @@ func (pool *TxPool) validateTx(ctx context.Context, tx *types.Transaction) error
 	// Check the transaction doesn't exceed the current
 	// block limit gas.
 	header := pool.chain.GetHeaderByHash(pool.head)
-	if header.GasLimit.Cmp(tx.Gas()) < 0 {
+	if header.GasLimit < tx.Gas() {
 		return core.ErrGasLimit
 	}
 
@@ -376,10 +376,13 @@ func (pool *TxPool) validateTx(ctx context.Context, tx *types.Transaction) error
 	}
 
 	// Should supply enough intrinsic gas
-	if tx.Gas().Cmp(core.IntrinsicGas(tx.Data(), tx.To() == nil, pool.homestead)) < 0 {
+	gas, err := core.IntrinsicGas(tx.Data(), tx.To() == nil, pool.homestead)
+	if err != nil {
+		return err
+	}
+	if tx.Gas() < gas {
 		return core.ErrIntrinsicGas
 	}
-
 	return currentState.Error()
 }
 
diff --git a/light/txpool_test.go b/light/txpool_test.go
index 2ef9e0cf5..b343f79b0 100644
--- a/light/txpool_test.go
+++ b/light/txpool_test.go
@@ -77,7 +77,7 @@ func txPoolTestChainGen(i int, block *core.BlockGen) {
 
 func TestTxPool(t *testing.T) {
 	for i := range testTx {
-		testTx[i], _ = types.SignTx(types.NewTransaction(uint64(i), acc1Addr, big.NewInt(10000), bigTxGas, nil, nil), types.HomesteadSigner{}, testBankKey)
+		testTx[i], _ = types.SignTx(types.NewTransaction(uint64(i), acc1Addr, big.NewInt(10000), params.TxGas, nil, nil), types.HomesteadSigner{}, testBankKey)
 	}
 
 	var (
diff --git a/miner/worker.go b/miner/worker.go
index c1f848e32..638f759bf 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -413,7 +413,6 @@ func (self *worker) commitNewWork() {
 		ParentHash: parent.Hash(),
 		Number:     num.Add(num, common.Big1),
 		GasLimit:   core.CalcGasLimit(parent),
-		GasUsed:    new(big.Int),
 		Extra:      self.extra,
 		Time:       big.NewInt(tstamp),
 	}
@@ -588,7 +587,7 @@ func (env *Work) commitTransactions(mux *event.TypeMux, txs *types.TransactionsB
 func (env *Work) commitTransaction(tx *types.Transaction, bc *core.BlockChain, coinbase common.Address, gp *core.GasPool) (error, []*types.Log) {
 	snap := env.state.Snapshot()
 
-	receipt, _, err := core.ApplyTransaction(env.config, bc, &coinbase, gp, env.state, env.header, tx, env.header.GasUsed, vm.Config{})
+	receipt, _, err := core.ApplyTransaction(env.config, bc, &coinbase, gp, env.state, env.header, tx, &env.header.GasUsed, vm.Config{})
 	if err != nil {
 		env.state.RevertToSnapshot(snap)
 		return err, nil
diff --git a/mobile/bind.go b/mobile/bind.go
index 7b79bedaf..1e861d0bc 100644
--- a/mobile/bind.go
+++ b/mobile/bind.go
@@ -77,7 +77,7 @@ func (opts *TransactOpts) GetFrom() *Address    { return &Address{opts.opts.From
 func (opts *TransactOpts) GetNonce() int64      { return opts.opts.Nonce.Int64() }
 func (opts *TransactOpts) GetValue() *BigInt    { return &BigInt{opts.opts.Value} }
 func (opts *TransactOpts) GetGasPrice() *BigInt { return &BigInt{opts.opts.GasPrice} }
-func (opts *TransactOpts) GetGasLimit() int64   { return opts.opts.GasLimit.Int64() }
+func (opts *TransactOpts) GetGasLimit() int64   { return int64(opts.opts.GasLimit) }
 
 // GetSigner cannot be reliably implemented without identity preservation (https://github.com/golang/go/issues/16876)
 // func (opts *TransactOpts) GetSigner() Signer { return &signer{opts.opts.Signer} }
@@ -99,7 +99,7 @@ func (opts *TransactOpts) SetSigner(s Signer) {
 }
 func (opts *TransactOpts) SetValue(value *BigInt)      { opts.opts.Value = value.bigint }
 func (opts *TransactOpts) SetGasPrice(price *BigInt)   { opts.opts.GasPrice = price.bigint }
-func (opts *TransactOpts) SetGasLimit(limit int64)     { opts.opts.GasLimit = big.NewInt(limit) }
+func (opts *TransactOpts) SetGasLimit(limit int64)     { opts.opts.GasLimit = uint64(limit) }
 func (opts *TransactOpts) SetContext(context *Context) { opts.opts.Context = context.context }
 
 // BoundContract is the base wrapper object that reflects a contract on the
diff --git a/mobile/ethclient.go b/mobile/ethclient.go
index 758863b6d..66399c6b5 100644
--- a/mobile/ethclient.go
+++ b/mobile/ethclient.go
@@ -298,9 +298,9 @@ func (ec *EthereumClient) SuggestGasPrice(ctx *Context) (price *BigInt, _ error)
 // the current pending state of the backend blockchain. There is no guarantee that this is
 // the true gas limit requirement as other transactions may be added or removed by miners,
 // but it should provide a basis for setting a reasonable default.
-func (ec *EthereumClient) EstimateGas(ctx *Context, msg *CallMsg) (gas *BigInt, _ error) {
+func (ec *EthereumClient) EstimateGas(ctx *Context, msg *CallMsg) (gas int64, _ error) {
 	rawGas, err := ec.client.EstimateGas(ctx.context, msg.msg)
-	return &BigInt{rawGas}, err
+	return int64(rawGas), err
 }
 
 // SendTransaction injects a signed transaction into the pending pool for execution.
diff --git a/mobile/ethereum.go b/mobile/ethereum.go
index c9bb3013c..0eb1d9055 100644
--- a/mobile/ethereum.go
+++ b/mobile/ethereum.go
@@ -20,7 +20,6 @@ package geth
 
 import (
 	"errors"
-	"math/big"
 
 	ethereum "github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
@@ -49,7 +48,7 @@ func NewCallMsg() *CallMsg {
 }
 
 func (msg *CallMsg) GetFrom() *Address    { return &Address{msg.msg.From} }
-func (msg *CallMsg) GetGas() int64        { return msg.msg.Gas.Int64() }
+func (msg *CallMsg) GetGas() int64        { return int64(msg.msg.Gas) }
 func (msg *CallMsg) GetGasPrice() *BigInt { return &BigInt{msg.msg.GasPrice} }
 func (msg *CallMsg) GetValue() *BigInt    { return &BigInt{msg.msg.Value} }
 func (msg *CallMsg) GetData() []byte      { return msg.msg.Data }
@@ -61,7 +60,7 @@ func (msg *CallMsg) GetTo() *Address {
 }
 
 func (msg *CallMsg) SetFrom(address *Address)  { msg.msg.From = address.address }
-func (msg *CallMsg) SetGas(gas int64)          { msg.msg.Gas = big.NewInt(gas) }
+func (msg *CallMsg) SetGas(gas int64)          { msg.msg.Gas = uint64(gas) }
 func (msg *CallMsg) SetGasPrice(price *BigInt) { msg.msg.GasPrice = price.bigint }
 func (msg *CallMsg) SetValue(value *BigInt)    { msg.msg.Value = value.bigint }
 func (msg *CallMsg) SetData(data []byte)       { msg.msg.Data = common.CopyBytes(data) }
diff --git a/mobile/types.go b/mobile/types.go
index b7f8a3bc1..4790afcef 100644
--- a/mobile/types.go
+++ b/mobile/types.go
@@ -112,8 +112,8 @@ func (h *Header) GetReceiptHash() *Hash  { return &Hash{h.header.ReceiptHash} }
 func (h *Header) GetBloom() *Bloom       { return &Bloom{h.header.Bloom} }
 func (h *Header) GetDifficulty() *BigInt { return &BigInt{h.header.Difficulty} }
 func (h *Header) GetNumber() int64       { return h.header.Number.Int64() }
-func (h *Header) GetGasLimit() int64     { return h.header.GasLimit.Int64() }
-func (h *Header) GetGasUsed() int64      { return h.header.GasUsed.Int64() }
+func (h *Header) GetGasLimit() int64     { return int64(h.header.GasLimit) }
+func (h *Header) GetGasUsed() int64      { return int64(h.header.GasUsed) }
 func (h *Header) GetTime() int64         { return h.header.Time.Int64() }
 func (h *Header) GetExtra() []byte       { return h.header.Extra }
 func (h *Header) GetMixDigest() *Hash    { return &Hash{h.header.MixDigest} }
@@ -189,8 +189,8 @@ func (b *Block) GetReceiptHash() *Hash  { return &Hash{b.block.ReceiptHash()} }
 func (b *Block) GetBloom() *Bloom       { return &Bloom{b.block.Bloom()} }
 func (b *Block) GetDifficulty() *BigInt { return &BigInt{b.block.Difficulty()} }
 func (b *Block) GetNumber() int64       { return b.block.Number().Int64() }
-func (b *Block) GetGasLimit() int64     { return b.block.GasLimit().Int64() }
-func (b *Block) GetGasUsed() int64      { return b.block.GasUsed().Int64() }
+func (b *Block) GetGasLimit() int64     { return int64(b.block.GasLimit()) }
+func (b *Block) GetGasUsed() int64      { return int64(b.block.GasUsed()) }
 func (b *Block) GetTime() int64         { return b.block.Time().Int64() }
 func (b *Block) GetExtra() []byte       { return b.block.Extra() }
 func (b *Block) GetMixDigest() *Hash    { return &Hash{b.block.MixDigest()} }
@@ -212,8 +212,8 @@ type Transaction struct {
 }
 
 // NewTransaction creates a new transaction with the given properties.
-func NewTransaction(nonce int64, to *Address, amount, gasLimit, gasPrice *BigInt, data []byte) *Transaction {
-	return &Transaction{types.NewTransaction(uint64(nonce), to.address, amount.bigint, gasLimit.bigint, gasPrice.bigint, common.CopyBytes(data))}
+func NewTransaction(nonce int64, to *Address, amount *BigInt, gasLimit int64, gasPrice *BigInt, data []byte) *Transaction {
+	return &Transaction{types.NewTransaction(uint64(nonce), to.address, amount.bigint, uint64(gasLimit), gasPrice.bigint, common.CopyBytes(data))}
 }
 
 // NewTransactionFromRLP parses a transaction from an RLP data dump.
@@ -256,7 +256,7 @@ func (tx *Transaction) String() string {
 }
 
 func (tx *Transaction) GetData() []byte      { return tx.tx.Data() }
-func (tx *Transaction) GetGas() int64        { return tx.tx.Gas().Int64() }
+func (tx *Transaction) GetGas() int64        { return int64(tx.tx.Gas()) }
 func (tx *Transaction) GetGasPrice() *BigInt { return &BigInt{tx.tx.GasPrice()} }
 func (tx *Transaction) GetValue() *BigInt    { return &BigInt{tx.tx.Value()} }
 func (tx *Transaction) GetNonce() int64      { return int64(tx.tx.Nonce()) }
@@ -353,10 +353,10 @@ func (r *Receipt) String() string {
 	return r.receipt.String()
 }
 
-func (r *Receipt) GetPostState() []byte          { return r.receipt.PostState }
-func (r *Receipt) GetCumulativeGasUsed() *BigInt { return &BigInt{r.receipt.CumulativeGasUsed} }
-func (r *Receipt) GetBloom() *Bloom              { return &Bloom{r.receipt.Bloom} }
-func (r *Receipt) GetLogs() *Logs                { return &Logs{r.receipt.Logs} }
-func (r *Receipt) GetTxHash() *Hash              { return &Hash{r.receipt.TxHash} }
-func (r *Receipt) GetContractAddress() *Address  { return &Address{r.receipt.ContractAddress} }
-func (r *Receipt) GetGasUsed() *BigInt           { return &BigInt{r.receipt.GasUsed} }
+func (r *Receipt) GetPostState() []byte         { return r.receipt.PostState }
+func (r *Receipt) GetCumulativeGasUsed() int64  { return int64(r.receipt.CumulativeGasUsed) }
+func (r *Receipt) GetBloom() *Bloom             { return &Bloom{r.receipt.Bloom} }
+func (r *Receipt) GetLogs() *Logs               { return &Logs{r.receipt.Logs} }
+func (r *Receipt) GetTxHash() *Hash             { return &Hash{r.receipt.TxHash} }
+func (r *Receipt) GetContractAddress() *Address { return &Address{r.receipt.ContractAddress} }
+func (r *Receipt) GetGasUsed() int64            { return int64(r.receipt.GasUsed) }
diff --git a/params/protocol_params.go b/params/protocol_params.go
index c56faf56f..5a0b14d61 100644
--- a/params/protocol_params.go
+++ b/params/protocol_params.go
@@ -18,7 +18,15 @@ package params
 
 import "math/big"
 
+var (
+	TargetGasLimit uint64 = GenesisGasLimit // The artificial target
+)
+
 const (
+	GasLimitBoundDivisor uint64 = 1024    // The bound divisor of the gas limit, used in update calculations.
+	MinGasLimit          uint64 = 5000    // Minimum the gas limit may ever be.
+	GenesisGasLimit      uint64 = 4712388 // Gas limit of the Genesis block.
+
 	MaximumExtraDataSize  uint64 = 32    // Maximum size extra data may be after Genesis.
 	ExpByteGas            uint64 = 10    // Times ceil(log256(exponent)) for the EXP instruction.
 	SloadGas              uint64 = 50    // Multiplied by the number of 32-byte words that are copied (round up) for any *COPY operation and added.
@@ -72,12 +80,8 @@ const (
 )
 
 var (
-	GasLimitBoundDivisor   = big.NewInt(1024)                  // The bound divisor of the gas limit, used in update calculations.
-	MinGasLimit            = big.NewInt(5000)                  // Minimum the gas limit may ever be.
-	GenesisGasLimit        = big.NewInt(4712388)               // Gas limit of the Genesis block.
-	TargetGasLimit         = new(big.Int).Set(GenesisGasLimit) // The artificial target
-	DifficultyBoundDivisor = big.NewInt(2048)                  // The bound divisor of the difficulty, used in the update calculations.
-	GenesisDifficulty      = big.NewInt(131072)                // Difficulty of the Genesis block.
-	MinimumDifficulty      = big.NewInt(131072)                // The minimum that the difficulty may ever be.
-	DurationLimit          = big.NewInt(13)                    // The decision boundary on the blocktime duration used to determine whether difficulty should go up or not.
+	DifficultyBoundDivisor = big.NewInt(2048)   // The bound divisor of the difficulty, used in the update calculations.
+	GenesisDifficulty      = big.NewInt(131072) // Difficulty of the Genesis block.
+	MinimumDifficulty      = big.NewInt(131072) // The minimum that the difficulty may ever be.
+	DurationLimit          = big.NewInt(13)     // The decision boundary on the blocktime duration used to determine whether difficulty should go up or not.
 )
diff --git a/tests/block_test_util.go b/tests/block_test_util.go
index a789e6d88..e2d1a0b43 100644
--- a/tests/block_test_util.go
+++ b/tests/block_test_util.go
@@ -77,8 +77,8 @@ type btHeader struct {
 	UncleHash        common.Hash
 	ExtraData        []byte
 	Difficulty       *big.Int
-	GasLimit         *big.Int
-	GasUsed          *big.Int
+	GasLimit         uint64
+	GasUsed          uint64
 	Timestamp        *big.Int
 }
 
@@ -86,8 +86,8 @@ type btHeaderMarshaling struct {
 	ExtraData  hexutil.Bytes
 	Number     *math.HexOrDecimal256
 	Difficulty *math.HexOrDecimal256
-	GasLimit   *math.HexOrDecimal256
-	GasUsed    *math.HexOrDecimal256
+	GasLimit   *math.HexOrDecimal64
+	GasUsed    *math.HexOrDecimal64
 	Timestamp  *math.HexOrDecimal256
 }
 
@@ -141,8 +141,8 @@ func (t *BlockTest) genesis(config *params.ChainConfig) *core.Genesis {
 		Timestamp:  t.json.Genesis.Timestamp.Uint64(),
 		ParentHash: t.json.Genesis.ParentHash,
 		ExtraData:  t.json.Genesis.ExtraData,
-		GasLimit:   t.json.Genesis.GasLimit.Uint64(),
-		GasUsed:    t.json.Genesis.GasUsed.Uint64(),
+		GasLimit:   t.json.Genesis.GasLimit,
+		GasUsed:    t.json.Genesis.GasUsed,
 		Difficulty: t.json.Genesis.Difficulty,
 		Mixhash:    t.json.Genesis.MixHash,
 		Coinbase:   t.json.Genesis.Coinbase,
@@ -234,11 +234,11 @@ func validateHeader(h *btHeader, h2 *types.Header) error {
 	if h.Difficulty.Cmp(h2.Difficulty) != 0 {
 		return fmt.Errorf("Difficulty: want: %v have: %v", h.Difficulty, h2.Difficulty)
 	}
-	if h.GasLimit.Cmp(h2.GasLimit) != 0 {
-		return fmt.Errorf("GasLimit: want: %v have: %v", h.GasLimit, h2.GasLimit)
+	if h.GasLimit != h2.GasLimit {
+		return fmt.Errorf("GasLimit: want: %d have: %d", h.GasLimit, h2.GasLimit)
 	}
-	if h.GasUsed.Cmp(h2.GasUsed) != 0 {
-		return fmt.Errorf("GasUsed: want: %v have: %v", h.GasUsed, h2.GasUsed)
+	if h.GasUsed != h2.GasUsed {
+		return fmt.Errorf("GasUsed: want: %d have: %d", h.GasUsed, h2.GasUsed)
 	}
 	if h.Timestamp.Cmp(h2.Time) != 0 {
 		return fmt.Errorf("Timestamp: want: %v have: %v", h.Timestamp, h2.Time)
diff --git a/tests/gen_btheader.go b/tests/gen_btheader.go
index 5d65e0dbc..1be659ecb 100644
--- a/tests/gen_btheader.go
+++ b/tests/gen_btheader.go
@@ -29,8 +29,8 @@ func (b btHeader) MarshalJSON() ([]byte, error) {
 		UncleHash        common.Hash
 		ExtraData        hexutil.Bytes
 		Difficulty       *math.HexOrDecimal256
-		GasLimit         *math.HexOrDecimal256
-		GasUsed          *math.HexOrDecimal256
+		GasLimit         math.HexOrDecimal64
+		GasUsed          math.HexOrDecimal64
 		Timestamp        *math.HexOrDecimal256
 	}
 	var enc btHeader
@@ -47,8 +47,8 @@ func (b btHeader) MarshalJSON() ([]byte, error) {
 	enc.UncleHash = b.UncleHash
 	enc.ExtraData = b.ExtraData
 	enc.Difficulty = (*math.HexOrDecimal256)(b.Difficulty)
-	enc.GasLimit = (*math.HexOrDecimal256)(b.GasLimit)
-	enc.GasUsed = (*math.HexOrDecimal256)(b.GasUsed)
+	enc.GasLimit = (math.HexOrDecimal64)(b.GasLimit)
+	enc.GasUsed = (math.HexOrDecimal64)(b.GasUsed)
 	enc.Timestamp = (*math.HexOrDecimal256)(b.Timestamp)
 	return json.Marshal(&enc)
 }
@@ -68,8 +68,8 @@ func (b *btHeader) UnmarshalJSON(input []byte) error {
 		UncleHash        *common.Hash
 		ExtraData        hexutil.Bytes
 		Difficulty       *math.HexOrDecimal256
-		GasLimit         *math.HexOrDecimal256
-		GasUsed          *math.HexOrDecimal256
+		GasLimit         *math.HexOrDecimal64
+		GasUsed          *math.HexOrDecimal64
 		Timestamp        *math.HexOrDecimal256
 	}
 	var dec btHeader
@@ -116,10 +116,10 @@ func (b *btHeader) UnmarshalJSON(input []byte) error {
 		b.Difficulty = (*big.Int)(dec.Difficulty)
 	}
 	if dec.GasLimit != nil {
-		b.GasLimit = (*big.Int)(dec.GasLimit)
+		b.GasLimit = uint64(*dec.GasLimit)
 	}
 	if dec.GasUsed != nil {
-		b.GasUsed = (*big.Int)(dec.GasUsed)
+		b.GasUsed = uint64(*dec.GasUsed)
 	}
 	if dec.Timestamp != nil {
 		b.Timestamp = (*big.Int)(dec.Timestamp)
diff --git a/tests/gen_stenv.go b/tests/gen_stenv.go
index c780524bc..1d4baf2fd 100644
--- a/tests/gen_stenv.go
+++ b/tests/gen_stenv.go
@@ -17,14 +17,14 @@ func (s stEnv) MarshalJSON() ([]byte, error) {
 	type stEnv struct {
 		Coinbase   common.UnprefixedAddress `json:"currentCoinbase"   gencodec:"required"`
 		Difficulty *math.HexOrDecimal256    `json:"currentDifficulty" gencodec:"required"`
-		GasLimit   *math.HexOrDecimal256    `json:"currentGasLimit"   gencodec:"required"`
+		GasLimit   math.HexOrDecimal64      `json:"currentGasLimit"   gencodec:"required"`
 		Number     math.HexOrDecimal64      `json:"currentNumber"     gencodec:"required"`
 		Timestamp  math.HexOrDecimal64      `json:"currentTimestamp"  gencodec:"required"`
 	}
 	var enc stEnv
 	enc.Coinbase = common.UnprefixedAddress(s.Coinbase)
 	enc.Difficulty = (*math.HexOrDecimal256)(s.Difficulty)
-	enc.GasLimit = (*math.HexOrDecimal256)(s.GasLimit)
+	enc.GasLimit = math.HexOrDecimal64(s.GasLimit)
 	enc.Number = math.HexOrDecimal64(s.Number)
 	enc.Timestamp = math.HexOrDecimal64(s.Timestamp)
 	return json.Marshal(&enc)
@@ -34,7 +34,7 @@ func (s *stEnv) UnmarshalJSON(input []byte) error {
 	type stEnv struct {
 		Coinbase   *common.UnprefixedAddress `json:"currentCoinbase"   gencodec:"required"`
 		Difficulty *math.HexOrDecimal256     `json:"currentDifficulty" gencodec:"required"`
-		GasLimit   *math.HexOrDecimal256     `json:"currentGasLimit"   gencodec:"required"`
+		GasLimit   *math.HexOrDecimal64      `json:"currentGasLimit"   gencodec:"required"`
 		Number     *math.HexOrDecimal64      `json:"currentNumber"     gencodec:"required"`
 		Timestamp  *math.HexOrDecimal64      `json:"currentTimestamp"  gencodec:"required"`
 	}
@@ -53,7 +53,7 @@ func (s *stEnv) UnmarshalJSON(input []byte) error {
 	if dec.GasLimit == nil {
 		return errors.New("missing required field 'currentGasLimit' for stEnv")
 	}
-	s.GasLimit = (*big.Int)(dec.GasLimit)
+	s.GasLimit = uint64(*dec.GasLimit)
 	if dec.Number == nil {
 		return errors.New("missing required field 'currentNumber' for stEnv")
 	}
diff --git a/tests/gen_tttransaction.go b/tests/gen_tttransaction.go
index b6759be91..840bdfdd8 100644
--- a/tests/gen_tttransaction.go
+++ b/tests/gen_tttransaction.go
@@ -17,7 +17,7 @@ var _ = (*ttTransactionMarshaling)(nil)
 func (t ttTransaction) MarshalJSON() ([]byte, error) {
 	type ttTransaction struct {
 		Data     hexutil.Bytes         `gencodec:"required"`
-		GasLimit *math.HexOrDecimal256 `gencodec:"required"`
+		GasLimit math.HexOrDecimal64   `gencodec:"required"`
 		GasPrice *math.HexOrDecimal256 `gencodec:"required"`
 		Nonce    math.HexOrDecimal64   `gencodec:"required"`
 		Value    *math.HexOrDecimal256 `gencodec:"required"`
@@ -28,7 +28,7 @@ func (t ttTransaction) MarshalJSON() ([]byte, error) {
 	}
 	var enc ttTransaction
 	enc.Data = t.Data
-	enc.GasLimit = (*math.HexOrDecimal256)(t.GasLimit)
+	enc.GasLimit = (math.HexOrDecimal64)(t.GasLimit)
 	enc.GasPrice = (*math.HexOrDecimal256)(t.GasPrice)
 	enc.Nonce = math.HexOrDecimal64(t.Nonce)
 	enc.Value = (*math.HexOrDecimal256)(t.Value)
@@ -42,7 +42,7 @@ func (t ttTransaction) MarshalJSON() ([]byte, error) {
 func (t *ttTransaction) UnmarshalJSON(input []byte) error {
 	type ttTransaction struct {
 		Data     hexutil.Bytes         `gencodec:"required"`
-		GasLimit *math.HexOrDecimal256 `gencodec:"required"`
+		GasLimit *math.HexOrDecimal64  `gencodec:"required"`
 		GasPrice *math.HexOrDecimal256 `gencodec:"required"`
 		Nonce    *math.HexOrDecimal64  `gencodec:"required"`
 		Value    *math.HexOrDecimal256 `gencodec:"required"`
@@ -62,7 +62,7 @@ func (t *ttTransaction) UnmarshalJSON(input []byte) error {
 	if dec.GasLimit == nil {
 		return errors.New("missing required field 'gasLimit' for ttTransaction")
 	}
-	t.GasLimit = (*big.Int)(dec.GasLimit)
+	t.GasLimit = uint64(*dec.GasLimit)
 	if dec.GasPrice == nil {
 		return errors.New("missing required field 'gasPrice' for ttTransaction")
 	}
diff --git a/tests/state_test_util.go b/tests/state_test_util.go
index 1f4fb2bd5..78c05b024 100644
--- a/tests/state_test_util.go
+++ b/tests/state_test_util.go
@@ -76,7 +76,7 @@ type stPostState struct {
 type stEnv struct {
 	Coinbase   common.Address `json:"currentCoinbase"   gencodec:"required"`
 	Difficulty *big.Int       `json:"currentDifficulty" gencodec:"required"`
-	GasLimit   *big.Int       `json:"currentGasLimit"   gencodec:"required"`
+	GasLimit   uint64         `json:"currentGasLimit"   gencodec:"required"`
 	Number     uint64         `json:"currentNumber"     gencodec:"required"`
 	Timestamp  uint64         `json:"currentTimestamp"  gencodec:"required"`
 }
@@ -84,7 +84,7 @@ type stEnv struct {
 type stEnvMarshaling struct {
 	Coinbase   common.UnprefixedAddress
 	Difficulty *math.HexOrDecimal256
-	GasLimit   *math.HexOrDecimal256
+	GasLimit   math.HexOrDecimal64
 	Number     math.HexOrDecimal64
 	Timestamp  math.HexOrDecimal64
 }
@@ -180,7 +180,7 @@ func (t *StateTest) genesis(config *params.ChainConfig) *core.Genesis {
 		Config:     config,
 		Coinbase:   t.json.Env.Coinbase,
 		Difficulty: t.json.Env.Difficulty,
-		GasLimit:   t.json.Env.GasLimit.Uint64(),
+		GasLimit:   t.json.Env.GasLimit,
 		Number:     t.json.Env.Number,
 		Timestamp:  t.json.Env.Timestamp,
 		Alloc:      t.json.Pre,
@@ -233,7 +233,7 @@ func (tx *stTransaction) toMessage(ps stPostState) (core.Message, error) {
 		return nil, fmt.Errorf("invalid tx data %q", dataHex)
 	}
 
-	msg := types.NewMessage(from, to, tx.Nonce, value, new(big.Int).SetUint64(gasLimit), tx.GasPrice, data, true)
+	msg := types.NewMessage(from, to, tx.Nonce, value, gasLimit, tx.GasPrice, data, true)
 	return msg, nil
 }
 
diff --git a/tests/transaction_test_util.go b/tests/transaction_test_util.go
index 472b3d6f2..2028d2a27 100644
--- a/tests/transaction_test_util.go
+++ b/tests/transaction_test_util.go
@@ -46,7 +46,7 @@ type ttJSON struct {
 
 type ttTransaction struct {
 	Data     []byte         `gencodec:"required"`
-	GasLimit *big.Int       `gencodec:"required"`
+	GasLimit uint64         `gencodec:"required"`
 	GasPrice *big.Int       `gencodec:"required"`
 	Nonce    uint64         `gencodec:"required"`
 	Value    *big.Int       `gencodec:"required"`
@@ -58,7 +58,7 @@ type ttTransaction struct {
 
 type ttTransactionMarshaling struct {
 	Data     hexutil.Bytes
-	GasLimit *math.HexOrDecimal256
+	GasLimit math.HexOrDecimal64
 	GasPrice *math.HexOrDecimal256
 	Nonce    math.HexOrDecimal64
 	Value    *math.HexOrDecimal256
@@ -100,8 +100,8 @@ func (tt *ttTransaction) verify(signer types.Signer, tx *types.Transaction) erro
 	if !bytes.Equal(tx.Data(), tt.Data) {
 		return fmt.Errorf("Tx input data mismatch: got %x want %x", tx.Data(), tt.Data)
 	}
-	if tx.Gas().Cmp(tt.GasLimit) != 0 {
-		return fmt.Errorf("GasLimit mismatch: got %v, want %v", tx.Gas(), tt.GasLimit)
+	if tx.Gas() != tt.GasLimit {
+		return fmt.Errorf("GasLimit mismatch: got %d, want %d", tx.Gas(), tt.GasLimit)
 	}
 	if tx.GasPrice().Cmp(tt.GasPrice) != 0 {
 		return fmt.Errorf("GasPrice mismatch: got %v, want %v", tx.GasPrice(), tt.GasPrice)