BigRuss

Okay, I've been searching for answers here but there really isn't much of a consensus as to what the best choice is for the following: header gasket material, to double-up or not to double-up, hi-temp silicone or dry, or whether to match the port or the header as far as the best gasket shape. In my experience, when an equal number of people disagree on all sides, there is usually more than one correct answer (or combination of answers).

First off: gasket material. I've seen people say to avoid the paper gaskets altogether, while some say to just double gasket and never look back. Aluminum and to a lesser extent copper has been claimed to be the bee's knees. My question, which I can't find any discussion on, is whether copper or aluminum are really good ideas considering the fact that these materials make excellent heat conductors. Headers put off tons of heat, and transferring a sizable portion of that heat to the heads doesn't sound like a good idea to me. Sounds like a recipe for faster head warping and head gasket wear. Paper or laminate materials would make much better heat insulators. Anyone have any insight here?

Also, consider when the port on the head is either square or D shaped and the header port is round. When picking a gasket, some have said to always match the port on the head, while others say match the round port on the header. Which is right (or wrong)? Please back this up with a pretty good reason if you can, not just that some wrench turner swears by it. My opinion, FWIW, is that you would probably want as little gasket material exposed to raw exhaust gases as possible. Meaning whichever port is larger - the header or head - is the port you want to match the gasket to. BTW, what would be the standard exhaust port dimensions for an '85 SBC?

Finally, the sealant. Obviously putting sealant on gives you a better chance of maintaining a seal, but is it really necessary and for which types of gaskets? Paper or laminate gaskets only? No sealant would make removal easier if necessary... a must for someone constantly swapping parts or tinkering; but if the headers are gonna stay put for a while would sealant be a must?