diff --git a/beacon_node/http_api/tests/tests.rs b/beacon_node/http_api/tests/tests.rs
index 2e795e522d..7267a1ccae 100644
--- a/beacon_node/http_api/tests/tests.rs
+++ b/beacon_node/http_api/tests/tests.rs
@@ -2122,7 +2122,7 @@ impl ApiTester {
         self
     }
 
-    pub async fn test_blinded_block_production<Payload: ExecPayload<E>>(&self) {
+    pub async fn test_blinded_block_production<Payload: AbstractExecPayload<E>>(&self) {
         let fork = self.chain.canonical_head.cached_head().head_fork();
         let genesis_validators_root = self.chain.genesis_validators_root;
 
@@ -2182,7 +2182,7 @@ impl ApiTester {
         }
     }
 
-    pub async fn test_blinded_block_production_no_verify_randao<Payload: ExecPayload<E>>(
+    pub async fn test_blinded_block_production_no_verify_randao<Payload: AbstractExecPayload<E>>(
         self,
     ) -> Self {
         for _ in 0..E::slots_per_epoch() {
@@ -2206,7 +2206,7 @@ impl ApiTester {
         self
     }
 
-    pub async fn test_blinded_block_production_verify_randao_invalid<Payload: ExecPayload<E>>(
+    pub async fn test_blinded_block_production_verify_randao_invalid<Payload: AbstractExecPayload<E>>(
         self,
     ) -> Self {
         let fork = self.chain.canonical_head.cached_head().head_fork();
@@ -2664,11 +2664,13 @@ impl ApiTester {
 
         let (proposer_index, randao_reveal) = self.get_test_randao(slot, epoch).await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -2677,10 +2679,10 @@ impl ApiTester {
 
         let expected_fee_recipient = Address::from_low_u64_be(proposer_index as u64);
         assert_eq!(
-            payload.execution_payload_header.fee_recipient,
+            payload.to_execution_payload_header().fee_recipient(),
             expected_fee_recipient
         );
-        assert_eq!(payload.execution_payload_header.gas_limit, 11_111_111);
+        assert_eq!(payload.to_execution_payload_header().gas_limit(), 11_111_111);
 
         // If this cache is empty, it indicates fallback was not used, so the payload came from the
         // mock builder.
@@ -2707,11 +2709,13 @@ impl ApiTester {
 
         let (proposer_index, randao_reveal) = self.get_test_randao(slot, epoch).await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -2720,10 +2724,10 @@ impl ApiTester {
 
         let expected_fee_recipient = Address::from_low_u64_be(proposer_index as u64);
         assert_eq!(
-            payload.execution_payload_header.fee_recipient,
+            payload.to_execution_payload_header().fee_recipient(),
             expected_fee_recipient
         );
-        assert_eq!(payload.execution_payload_header.gas_limit, 30_000_000);
+        assert_eq!(payload.to_execution_payload_header().gas_limit(), 30_000_000);
 
         // This cache should not be populated because fallback should not have been used.
         assert!(self
@@ -2753,11 +2757,13 @@ impl ApiTester {
 
         let (_, randao_reveal) = self.get_test_randao(slot, epoch).await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+            
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -2765,7 +2771,7 @@ impl ApiTester {
             .clone();
 
         assert_eq!(
-            payload.execution_payload_header.fee_recipient,
+            payload.to_execution_payload_header().fee_recipient(),
             test_fee_recipient
         );
 
@@ -2801,15 +2807,17 @@ impl ApiTester {
             .beacon_state
             .latest_execution_payload_header()
             .unwrap()
-            .block_hash;
+            .block_hash();
 
         let (_, randao_reveal) = self.get_test_randao(slot, epoch).await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -2817,7 +2825,7 @@ impl ApiTester {
             .clone();
 
         assert_eq!(
-            payload.execution_payload_header.parent_hash,
+            payload.to_execution_payload_header().parent_hash(),
             expected_parent_hash
         );
 
@@ -2856,11 +2864,13 @@ impl ApiTester {
 
         let (_, randao_reveal) = self.get_test_randao(slot, epoch).await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -2868,7 +2878,7 @@ impl ApiTester {
             .clone();
 
         assert_eq!(
-            payload.execution_payload_header.prev_randao,
+            payload.to_execution_payload_header().prev_randao(),
             expected_prev_randao
         );
 
@@ -2901,16 +2911,18 @@ impl ApiTester {
             .beacon_state
             .latest_execution_payload_header()
             .unwrap()
-            .block_number
+            .block_number()
             + 1;
 
         let (_, randao_reveal) = self.get_test_randao(slot, epoch).await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -2918,7 +2930,7 @@ impl ApiTester {
             .clone();
 
         assert_eq!(
-            payload.execution_payload_header.block_number,
+            payload.to_execution_payload_header().block_number(),
             expected_block_number
         );
 
@@ -2951,22 +2963,24 @@ impl ApiTester {
             .beacon_state
             .latest_execution_payload_header()
             .unwrap()
-            .timestamp;
+            .timestamp();
 
         let (_, randao_reveal) = self.get_test_randao(slot, epoch).await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
             .unwrap()
             .clone();
 
-        assert!(payload.execution_payload_header.timestamp > min_expected_timestamp);
+        assert!(payload.to_execution_payload_header().timestamp() > min_expected_timestamp);
 
         // If this cache is populated, it indicates fallback to the local EE was correctly used.
         assert!(self
@@ -2991,11 +3005,13 @@ impl ApiTester {
 
         let (_, randao_reveal) = self.get_test_randao(slot, epoch).await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+            
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -3028,11 +3044,13 @@ impl ApiTester {
 
         let (_, randao_reveal) = self.get_test_randao(slot, epoch).await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+            
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -3071,11 +3089,13 @@ impl ApiTester {
             .get_test_randao(next_slot, next_slot.epoch(E::slots_per_epoch()))
             .await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(next_slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -3100,11 +3120,13 @@ impl ApiTester {
             .get_test_randao(next_slot, next_slot.epoch(E::slots_per_epoch()))
             .await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(next_slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+            
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -3149,11 +3171,13 @@ impl ApiTester {
             .get_test_randao(next_slot, next_slot.epoch(E::slots_per_epoch()))
             .await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(next_slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -3187,12 +3211,14 @@ impl ApiTester {
         let (_, randao_reveal) = self
             .get_test_randao(next_slot, next_slot.epoch(E::slots_per_epoch()))
             .await;
-
-        let payload = self
+        
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(next_slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+            
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -3231,11 +3257,13 @@ impl ApiTester {
 
         let (proposer_index, randao_reveal) = self.get_test_randao(slot, epoch).await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+            
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()
@@ -3244,7 +3272,7 @@ impl ApiTester {
 
         let expected_fee_recipient = Address::from_low_u64_be(proposer_index as u64);
         assert_eq!(
-            payload.execution_payload_header.fee_recipient,
+            payload.to_execution_payload_header().fee_recipient(),
             expected_fee_recipient
         );
 
@@ -3275,11 +3303,13 @@ impl ApiTester {
 
         let (_, randao_reveal) = self.get_test_randao(slot, epoch).await;
 
-        let payload = self
+        let beacon_block_response = self
             .client
             .get_validator_blinded_blocks::<E, BlindedPayload<E>>(slot, &randao_reveal, None)
             .await
-            .unwrap()
+            .unwrap();
+            
+        let payload = beacon_block_response
             .data
             .body()
             .execution_payload()