I hate to make another Cometic sealing thread, but here it is. I removed my heads before firing the engine and this is what I found. A light coat of oil over the gasket (engine had been primed, for quite a long time until oil came to all rockers). The surface finish is right, and surfaces are completely flat. They were torqued to 85 FT/LBS (studs). I ran Cometics before on this engine with iron heads and but could not tell you if oil made it through the layers because the valvecover gaskets always leaked oil everywhere anyway. I am thinking of a light spray of copper sealer. In threads past some say yes, some no. I am having a hard time deciding but the oil is definately bothering me. FWIW I did retorque multiple times until it stopped taking additional torque
Have a look.
Have a look.