Best Valve Cover Gaskets Available?

Mopar (Mopar Performance) grey with steel insert.

I've run them for 10 years on my old 340 with cast aluminum Cal Custom valve covers and stock as-cast rough wavy not machined side rails on original cast iron X heads. Still good, I just put that motor aside to make way for my new stroker motor.

With a head that has machined valve cover rails they should be pretty indestructable.

I've been running those composite/paper covered rubber valve cover with machined Edelbrock heads and those cast aluminum valve covers. Not really any problems, but after 4-6 solid lifter valve adjustments the paper started to come undone. I put white lithium grease between head and gasket and that works real nice. But they have probably been off and on 10 times they started to stick to the head and come apart.

I'm putting on a new set of Grey MP steel core gaskets and I expect them to last 10 years like the last set.