The 6.0 liter Chevrolet engine uses an aluminum cylinder head and a cast-iron engine block. Torquing the head bolts correctly is vital because aluminum expands faster than iron when heated. Head bolts hold the block and the head together and the gasket between the two that seals the connection. The gasket is made of a composite material that is not as strong as either aluminum or cast iron. If the head bolts are too tight, the gasket may break. If the bolts are too loose, expanding gases from the combustion chamber may blow the gasket out.
Clean the head bolt holes with compressed air.
Examine the head bolts. The Chevy big block has two kinds of head bolts. Long bolts go all the way through from the top of the head into the water jacket. Short bolts have a blind hole that does not go all the way through. Coat the threads of short head bolts with motor oil and the threads of long bolts with thread sealant. The sealant has a very heavy consistency; it contains teflon that makes bolts easier to thread.
Consult the instructions that came from your head bolt kit. The final torque setting is 75 foot-pounds for long bolts and 65 foot-pounds for short bolts. The head bolts must be torqued in stages and in a definite sequence, usually starting with the inner bolts and moving outward. The instructions for the head bolts you install in your engine may ask you to tighten all the bolts to half the final value then start from the inside bolts and tighten them all the way.
Use a torque wrench to tighten the head bolts in the sequence and in the steps indicated in the head bolt kit.
