diff --git a/crates/engine/tree/src/tree/e2e_tests.rs b/crates/engine/tree/src/tree/e2e_tests.rs
index 0bbd92b8df..a2754d61ad 100644
--- a/crates/engine/tree/src/tree/e2e_tests.rs
+++ b/crates/engine/tree/src/tree/e2e_tests.rs
@@ -241,3 +241,31 @@ async fn test_engine_tree_buffered_blocks_are_eventually_connected_e2e() -> Resu
 
     Ok(())
 }
+
+/// Test that verifies forkchoice updates can extend the canonical chain progressively.
+///
+/// This test creates a longer chain of blocks, then uses forkchoice updates to make
+/// different parts of the chain canonical in sequence, verifying that FCU properly
+/// advances the canonical head when all blocks are already available.
+#[tokio::test]
+async fn test_engine_tree_fcu_extends_canon_chain_e2e() -> Result<()> {
+    reth_tracing::init_test_tracing();
+
+    let test = TestBuilder::new()
+        .with_setup(default_engine_tree_setup())
+        // create and make canonical a base chain with 1 block
+        .with_action(ProduceBlocks::<EthEngineTypes>::new(1))
+        .with_action(MakeCanonical::new())
+        // extend the chain with 10 more blocks (total 11 blocks: 0-10)
+        .with_action(ProduceBlocks::<EthEngineTypes>::new(10))
+        // capture block 6 as our intermediate target (from 0-indexed, this is block 6)
+        .with_action(CaptureBlock::new("target_block"))
+        // make the intermediate target canonical via FCU
+        .with_action(ReorgTo::<EthEngineTypes>::new_from_tag("target_block"))
+        // now make the chain tip canonical via FCU
+        .with_action(MakeCanonical::new());
+
+    test.run::<EthereumNode>().await?;
+
+    Ok(())
+}
diff --git a/crates/engine/tree/src/tree/tests.rs b/crates/engine/tree/src/tree/tests.rs
index 43891c6fb7..a00d4a56bd 100644
--- a/crates/engine/tree/src/tree/tests.rs
+++ b/crates/engine/tree/src/tree/tests.rs
@@ -219,16 +219,6 @@ impl TestHarness {
         self.evm_config.extend(execution_outcomes);
     }
 
-    fn insert_block(
-        &mut self,
-        block: RecoveredBlock<reth_ethereum_primitives::Block>,
-    ) -> Result<InsertPayloadOk, InsertBlockError<Block>> {
-        let execution_outcome = self.block_builder.get_execution_outcome(block.clone());
-        self.extend_execution_outcome([execution_outcome]);
-        self.tree.provider.add_state_root(block.state_root);
-        self.tree.insert_block(block)
-    }
-
     async fn fcu_to(&mut self, block_hash: B256, fcu_status: impl Into<ForkchoiceStatus>) {
         let fcu_status = fcu_status.into();
 
@@ -286,16 +276,6 @@ impl TestHarness {
         }
     }
 
-    async fn insert_chain(
-        &mut self,
-        chain: impl IntoIterator<Item = RecoveredBlock<reth_ethereum_primitives::Block>> + Clone,
-    ) {
-        for block in chain.clone() {
-            self.insert_block(block.clone()).unwrap();
-        }
-        self.check_canon_chain_insertion(chain).await;
-    }
-
     async fn check_canon_commit(&mut self, hash: B256) {
         let event = self.from_tree_rx.recv().await.unwrap();
         match event {
@@ -1034,44 +1014,3 @@ async fn test_engine_tree_live_sync_transition_eventually_canonical() {
     // new head is the tip of the main chain
     test_harness.check_canon_head(main_chain_last_hash);
 }
-
-#[tokio::test]
-async fn test_engine_tree_live_sync_fcu_extends_canon_chain() {
-    reth_tracing::init_test_tracing();
-
-    let chain_spec = MAINNET.clone();
-    let mut test_harness = TestHarness::new(chain_spec.clone());
-
-    // create base chain and setup test harness with it
-    let base_chain: Vec<_> = test_harness.block_builder.get_executed_blocks(0..1).collect();
-    test_harness = test_harness.with_blocks(base_chain.clone());
-
-    // fcu to the tip of base chain
-    test_harness
-        .fcu_to(base_chain.last().unwrap().recovered_block().hash(), ForkchoiceStatus::Valid)
-        .await;
-
-    // create main chain, extension of base chain
-    let main_chain = test_harness.block_builder.create_fork(base_chain[0].recovered_block(), 10);
-    // determine target in the middle of main hain
-    let target = main_chain.get(5).unwrap();
-    let target_hash = target.hash();
-    let main_last = main_chain.last().unwrap();
-    let main_last_hash = main_last.hash();
-
-    // insert main chain
-    test_harness.insert_chain(main_chain).await;
-
-    // send fcu to target
-    test_harness.send_fcu(target_hash, ForkchoiceStatus::Valid).await;
-
-    test_harness.check_canon_commit(target_hash).await;
-    test_harness.check_fcu(target_hash, ForkchoiceStatus::Valid).await;
-
-    // send fcu to main tip
-    test_harness.send_fcu(main_last_hash, ForkchoiceStatus::Valid).await;
-
-    test_harness.check_canon_commit(main_last_hash).await;
-    test_harness.check_fcu(main_last_hash, ForkchoiceStatus::Valid).await;
-    test_harness.check_canon_head(main_last_hash);
-}