[71 super]

What type of copper head gaskets? I have used "Copperhead" brand gaskets in the past and loved them. They served the intended purpose of avoiding "o" rings and killed off a little compression so the motor could be streeted. Best part throw them in the oven at 400* or so for a few and you can reuse them. Are you using head studs? If so are the they torqued using oil or ARP lube? Not pulling threads out of the block are you, that is if you are using regular head bolts? Had that problem once and the studs cured that. I agree that you need the seal threads, but think it is a problem lower than the intake.