It is just me? I cannot seem to get valve covers to seal. My '83 258 in the 1970 Hornet leaks like crazy. It's an aftermarket cast aluminum cover. It has the rubber gasket. I tapped the holes right. I had it grease-free (solvent then alcohol wipe) and gasket-cemented the cover, let it dry overnight. Snug, but not tight. Still leaks. Any suggestions? What exact gasket goop do people use for this app? Should I just buy a Felpro cork gasket, or something fancy?