Rich B.

This from the Sept 2001 issue of Chevy High Performance magazine:

"GM offered the L98 TPI small-block with two different cylinder heads. The Camaros had the cast-iron heads, and the lucky Corvette got the aluminum heads. The iron heads had 64cc combustion chambers, and the aluminum heads measured 58cc. Now, to keep the compression ratio the same between the two engines, GM used a thin .028-inch composition head gasket with the iron heads. This gasket displaced 6.05cc. The aluminum heads used a .051-inch head gasket that displaced 11cc. As you can see, the head gaskets offset the differences in cylinder head volumes. Now, the hot setup is to use the .028-inch iron head gaskets with aluminum heads, which bumps the compression up half a ratio, but that's another story!"

...Take it with a grain of salt... :D

65Z01

I believed their numbers when I read the article and will consider that path when doing my Al heads. The possible risk is that the composition of either gasket may (likely does) differ.

So my concern is the iron head gasket suitable for the Al head that expands differently from the block?? Usually gaskets for Al heads have a composition that allows for this one material sliding across the other during heating/cooling cycles.

zbo2

i know of no differances between head gaskets for aluminum heads and iron heads......and if there is any ( sliding ) going on you had better re-torque your heads... :smash:

GRX

I'm not sure, but, it's not advisable to mate aluminum heads to steel. Introduce some water and a voltaic corrosive situation arrises. That's why composition is used with Al heads. Also, I think those cc volumes that the magazine reports might be a tad off. I understood the iron heads where in the vicinity of 70-76cc's??? (with flat top pistons)

black bart

:nono: The expansion rate between aluminum and cast iron is much different and there is slippage. :yesnod: :yesnod:

zbo2

we use copper gaskets with all the aluminum headed race engines we build.