I have a set of corvette magnesium center bolt covers. The mounting bolt boss on them is .08” taller than my steel covers and the gaskets don’t touch the heads. Is this common? Do I need a special gasket for these?

 

When you looked it up on rockauto or autozone.com or some such, what did it look like?

 

This is an interesting problem. I have several pairs of different valve covers that I had thought about trying, these among them. Did not anticipate this issue.

For kicks, I looked up a pair of L98s...90 Camaro, and 90 Vette. In some instances (Engine Tech, Mahle / Clevite, Felpro, Elring), they list the same part #. In other cases (GM) they list them for one but not the other, or in the case of Victor Reinz, different numbers.

 

OK, so if they're different, buy the ones for the Vette. Ignore the wrinkles in the sheet metal (or fiberglass) and get what fits.

It's not that hard.