diff --git a/src/ethereum_test_fixtures/tests/test_blockchain.py b/src/ethereum_test_fixtures/tests/test_blockchain.py
index 343d38e6c7..c581119113 100644
--- a/src/ethereum_test_fixtures/tests/test_blockchain.py
+++ b/src/ethereum_test_fixtures/tests/test_blockchain.py
@@ -16,6 +16,7 @@
     Bytes,
     Hash,
     HeaderNonce,
+    HexNumber,
     TestPrivateKey,
     ZeroPaddedHexNumber,
     to_json,
@@ -790,7 +791,7 @@
                             max_request_type=2,
                         ).requests_list
                     ],
-                    hex(21),
+                    HexNumber(21).hex(),
                 ],
                 "forkchoiceUpdatedVersion": "4",
                 "newPayloadVersion": "4",
@@ -948,7 +949,7 @@
                             max_request_type=2,
                         ).requests_list
                     ],
-                    hex(21),
+                    HexNumber(21).hex(),
                 ],
                 "newPayloadVersion": "4",
                 "forkchoiceUpdatedVersion": "4",
@@ -1171,7 +1172,7 @@ def test_json_deserialization(
             id="fixture_engine_new_payload_parameters_v3",
         ),
         pytest.param(
-            False,
+            True,
             EngineNewPayloadParametersAdapter,
             (
                 FixtureExecutionPayload.from_fixture_header(
@@ -1195,7 +1196,6 @@ def test_json_deserialization(
                         withdrawals_root=Hash(16),
                         blob_gas_used=17,
                         excess_blob_gas=18,
-                        target_blobs_per_block=10,
                     ),
                     transactions=[
                         Transaction(
@@ -1237,6 +1237,7 @@ def test_json_deserialization(
                     ),
                     max_request_type=2,
                 ).requests_list,
+                HexNumber(9),
             ),
             [
                 {
@@ -1254,7 +1255,6 @@ def test_json_deserialization(
                     "baseFeePerGas": hex(15),
                     "blobGasUsed": hex(17),
                     "excessBlobGas": hex(18),
-                    "targetBlobCount": hex(10),
                     "blockHash": "0xd90115b7fde329f64335763a446af1"
                     "50ab67e639281dccdb07a007d18bb80211",
                     "transactions": [
@@ -1304,6 +1304,7 @@ def test_json_deserialization(
                         max_request_type=2,
                     ).requests_list
                 ],
+                HexNumber(9).hex(),
             ],
             id="fixture_engine_new_payload_parameters_v4",
         ),