NOTE: Before beginning, make sure that the engine is completely cool and that all of the necessary tools and materials are on hand.
Required Tools and Materials:
-Torque wrench
-Socket set
-Wrench
-Rags
-Penetrating oil
-Thread sealant
Torque Specifications:
-Cylinder Head Bolts: 65-70 ft-lbs
-Exhaust Manifold Bolts: 25-30 ft-lbs
Torque Sequence:
Step 1: Cylinder Head Bolts
-Start by removing the valve covers and spark plugs to gain access to the cylinder head bolts.
-Use penetrating oil on the bolts to help break free any corrosion or rust.
-Begin by tightening the corner bolts first, making sure to do them in opposing corners such as;
1 and 8
2 and 7
3 and 6
4 and 5
(see image for numbering)
-Once the corner bolts are snug, tighten the remaining bolts in a criss-cross pattern.
-Tighten the bolts to 65-70 ft-lbs using a torque wrench.
-Ensure the threads are clean and damage-free.
-Apply a small amount of thread sealant to the bolts before tightening them.
Step 2: Exhaust Manifold Bolts
-Remove the old exhaust manifold gaskets and clean the mating surfaces of the manifold and cylinder head.
-Place the new gaskets in position and install the exhaust manifold bolts. Tighten the bolts to 25-30 ft-lbs.
-Repeat the process for the other exhaust manifold.
-Start the engine and check for any leaks. If any leaks are present, tighten the bolts further.
It's important to follow the proper torque sequence and specifications to ensure proper sealing and performance of the cylinder heads and exhaust manifolds on your Chevy 454 engine.
