i just bought a 1978 malibu and it has a valve cover leak that i can't get corrected. i have changed the gasket(2 rubber, 1 cork) and the valve cover itself and it still leaks.all the holes in the head are clear. i know it's something stupid i'm just overlooking but if someone could help me out i'd appreciate it.

Warped valve cover from prying it off maybe?

i have changed the gasket(2 rubber, 1 cork) and the valve cover itself

check your pcv valve and breather. If either is clogged or disconnected, it can cause too much pressure to build up in the crankcase, and leak out the valve cover. If that's not the problem, then check the surface of the head to see if it's flat.