diff --git a/src/testing/testing_buildBlockV1.yaml b/src/testing/testing_buildBlockV1.yaml
index 5b60e0342..d40f989f9 100644
--- a/src/testing/testing_buildBlockV1.yaml
+++ b/src/testing/testing_buildBlockV1.yaml
@@ -23,7 +23,7 @@
     - name: Payload attributes
       required: true
       schema:
-        title: PayloadAttributesV3
+        title: PayloadAttributesV4
         type: object
         properties:
           timestamp:
@@ -39,6 +39,10 @@
               $ref: '#/components/schemas/Withdrawal'
           parentBeaconBlockRoot:
             $ref: '#/components/schemas/hash32'
+          slotNumber:
+            $ref: '#/components/schemas/uint'
+          targetGasLimit:
+            $ref: '#/components/schemas/uint'
     - name: Transactions
       required: true
       description: |
@@ -106,6 +110,8 @@
             suggestedFeeRecipient: '0x0000000000000000000000000000000000000000'
             withdrawals: []
             parentBeaconBlockRoot: '0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884365149a42212e8822'
+            slotNumber: '0x0'
+            targetGasLimit: '0x1c9c380'
         - name: Transactions
           value: []
         - name: Extra data
diff --git a/tools/testgen/generators.go b/tools/testgen/generators.go
index 97230b54e..0b7077094 100644
--- a/tools/testgen/generators.go
+++ b/tools/testgen/generators.go
@@ -2732,6 +2732,11 @@ var TestingBuildBlockV1 = MethodTests{
 					payloadAttrs["parentBeaconBlockRoot"] = beaconRoot.Hex()
 				}
 
+				if t.chain.Config().IsAmsterdam(parentBlock.Number(), parentBlock.Time()) {
+					payloadAttrs["slotNumber"] = hexutil.Uint64(0)
+					payloadAttrs["targetGasLimit"] = hexutil.Uint64(parentBlock.GasLimit())
+				}
+
 				// Use sender index 2 so nonce matches geth state: index 0 (and 3) are used by
 				// eth_sendRawTransaction tests which call IncNonce, so they diverge from geth when run in full suite.
 				sender, nonce := t.chain.GetSender(2)
@@ -2821,6 +2826,11 @@ var TestingBuildBlockV1 = MethodTests{
 					payloadAttrs["parentBeaconBlockRoot"] = beaconRoot.Hex()
 				}
 
+				if t.chain.Config().IsAmsterdam(parentBlock.Number(), parentBlock.Time()) {
+					payloadAttrs["slotNumber"] = hexutil.Uint64(0)
+					payloadAttrs["targetGasLimit"] = hexutil.Uint64(parentBlock.GasLimit())
+				}
+
 				extraData := hexutil.Encode([]byte{})
 				var result map[string]interface{}
 				err := t.rpc.CallContext(ctx, &result, "testing_buildBlockV1",
@@ -2875,6 +2885,11 @@ var TestingBuildBlockV1 = MethodTests{
 					payloadAttrs["parentBeaconBlockRoot"] = beaconRoot.Hex()
 				}
 
+				if t.chain.Config().IsAmsterdam(parentBlock.Number(), parentBlock.Time()) {
+					payloadAttrs["slotNumber"] = hexutil.Uint64(0)
+					payloadAttrs["targetGasLimit"] = hexutil.Uint64(parentBlock.GasLimit())
+				}
+
 				// Add a transaction to the mempool first
 				sender, nonce := t.chain.GetSender(1)
 				basefee := parentBlock.BaseFee()
@@ -2957,6 +2972,11 @@ var TestingBuildBlockV1 = MethodTests{
 					payloadAttrs["parentBeaconBlockRoot"] = beaconRoot.Hex()
 				}
 
+				if t.chain.Config().IsAmsterdam(parentBlock.Number(), parentBlock.Time()) {
+					payloadAttrs["slotNumber"] = hexutil.Uint64(0)
+					payloadAttrs["targetGasLimit"] = hexutil.Uint64(parentBlock.GasLimit())
+				}
+
 				// Use an invalid nonce (e.g. 999) so the tx cannot be applied; client MUST fail.
 				sender, _ := t.chain.GetSender(2)
 				basefee := parentBlock.BaseFee()