I have a pair of aluminum heads off of a corvette and i was wondering if i can use a steel shim for headgaskets or do i have to use the factory head gaskets? and i am wondering what head bolts i can use? can i use my cast iron head bolts or do i have to buy new ones? i know with most alum head applications they recomend you buying new headbolts but i like to know what the story is.

 

anyone?

 

Not sure about the head gaskets, but you should use new head bolts with the machined flat washers needed for aluminum heads.

 

yeah i used arp head bolts w/ washers with my edelbrock rpm heads...... and i used stock headgaskets for a regular cast iron head SBC

 

A thin steel shim head gasket can be used with a aluminum head but you may get some galvanatic action ( corrosion) between the head and block because of the electrolitic action of the disssimular metals. It takes a long time for this corrosion to happen. Same as the water port openings will corrode over time on a aluminum manifold and steel heads.
using good antifreeze with corrosion additives or some "Water Wetter" in the cooling system will help a lot too.
If you're going to use a thicker composite gasket get on designed to not "brinnell" the aluminum head surface. (indent the head) (softer preflattened copper fire ring).

Reguardless of which gasket retorque the head bolts after a few warm up cycles. the head bolts will need hardened washers under the heads of each bolt.

 

Use the stock GM .038 gasket or the performance GM .028 gasket to boost compression.

 

aluminum expands more than steel does when it gets hot, but then it cools faster than steel does. You'll be getting a lot of shearing of the gasket. it's best to use a standard OEM style FelPro gasket. You could try your luck with a steel shim gasket but as mentioned about the galvanic action, you might get rust that glues the head to the block