diff --git a/core/types/block.go b/core/types/block.go
index 404edca818..01c723c475 100644
--- a/core/types/block.go
+++ b/core/types/block.go
@@ -126,53 +126,6 @@ func NewBlock(
 	return b
 }
 
-// CopyHeader creates a deep copy of a block header.
-func CopyHeader(h *Header) *Header {
-	cpy := *h
-	hExtra := GetHeaderExtra(h)
-	cpyExtra := &HeaderExtra{
-		ExtDataHash: hExtra.ExtDataHash,
-	}
-	SetHeaderExtra(&cpy, cpyExtra)
-
-	if cpy.Difficulty = new(big.Int); h.Difficulty != nil {
-		cpy.Difficulty.Set(h.Difficulty)
-	}
-	if cpy.Number = new(big.Int); h.Number != nil {
-		cpy.Number.Set(h.Number)
-	}
-	if h.BaseFee != nil {
-		cpy.BaseFee = new(big.Int).Set(h.BaseFee)
-	}
-	if hExtra.ExtDataGasUsed != nil {
-		cpyExtra.ExtDataGasUsed = new(big.Int).Set(hExtra.ExtDataGasUsed)
-	}
-	if hExtra.BlockGasCost != nil {
-		cpyExtra.BlockGasCost = new(big.Int).Set(hExtra.BlockGasCost)
-	}
-	if len(h.Extra) > 0 {
-		cpy.Extra = make([]byte, len(h.Extra))
-		copy(cpy.Extra, h.Extra)
-	}
-	if h.WithdrawalsHash != nil {
-		cpy.WithdrawalsHash = new(common.Hash)
-		*cpy.WithdrawalsHash = *h.WithdrawalsHash
-	}
-	if h.ExcessBlobGas != nil {
-		cpy.ExcessBlobGas = new(uint64)
-		*cpy.ExcessBlobGas = *h.ExcessBlobGas
-	}
-	if h.BlobGasUsed != nil {
-		cpy.BlobGasUsed = new(uint64)
-		*cpy.BlobGasUsed = *h.BlobGasUsed
-	}
-	if h.ParentBeaconRoot != nil {
-		cpy.ParentBeaconRoot = new(common.Hash)
-		*cpy.ParentBeaconRoot = *h.ParentBeaconRoot
-	}
-	return &cpy
-}
-
 // DecodeRLP decodes a block from RLP.
 func (b *Block) DecodeRLP(s *rlp.Stream) error {
 	var eb extblock
diff --git a/core/types/header_ext.go b/core/types/header_ext.go
index 1e6ebd5bf8..ad83f8ec4b 100644
--- a/core/types/header_ext.go
+++ b/core/types/header_ext.go
@@ -84,7 +84,16 @@ func (h *HeaderExtra) DecodeJSON(eth *ethtypes.Header, input []byte) error {
 }
 
 func (h *HeaderExtra) PostCopy(dst *ethtypes.Header) {
-	panic("not implemented")
+	cp := &HeaderExtra{
+		ExtDataHash: h.ExtDataHash,
+	}
+	if h.BlockGasCost != nil {
+		cp.BlockGasCost = new(big.Int).Set(h.BlockGasCost)
+	}
+	if h.ExtDataGasUsed != nil {
+		cp.ExtDataGasUsed = new(big.Int).Set(h.ExtDataGasUsed)
+	}
+	SetHeaderExtra(dst, cp)
 }
 
 func (h *HeaderSerializable) updateFromEth(eth *ethtypes.Header) {
diff --git a/core/types/header_ext_test.go b/core/types/header_ext_test.go
index 97b22237b3..769052a552 100644
--- a/core/types/header_ext_test.go
+++ b/core/types/header_ext_test.go
@@ -168,4 +168,6 @@ func assertNonZero[T interface {
 	}
 }
 
+// Note [TestCopyHeader] tests the [HeaderExtra.PostCopy] method.
+
 func ptrTo[T any](x T) *T { return &x }
diff --git a/core/types/imports.go b/core/types/imports.go
index cc25fa9a8e..e630ea5366 100644
--- a/core/types/imports.go
+++ b/core/types/imports.go
@@ -51,6 +51,7 @@ const (
 var (
 	BloomLookup          = ethtypes.BloomLookup
 	BytesToBloom         = ethtypes.BytesToBloom
+	CopyHeader           = ethtypes.CopyHeader
 	CreateBloom          = ethtypes.CreateBloom
 	EncodeNonce          = ethtypes.EncodeNonce
 	FullAccount          = ethtypes.FullAccount