Okay Ive been through the cork ones tried the rubber
I just installed a set of the Moroso rubber ones and
both sides leaked.
I have a 440 with eddy heads and arp valve cover studs.
The valve covers are the mopar perf ones.
These moroso gaskets are really nice when I got them I thought my troubles were gone. I put them on with no sealer both sides leaked at the bottom right over the headers. The mopar valve covers have these round
holes on the sealing surface of them they look like from casting them.Wondering if I should put some rtv between the covers and the gaskets.
I have the usual setup for pcv the breather on the
drivers side the pcv on the pass.Any help would be welcome cause Im getting burnt out on this. thanks.

I use the Fel-pro rubber ones. I like to use 3M weatherstrip adhesive tween the gasket and the cover, I glue the gaskets in place and set the covers on a hard FLAT surface for at least a few hours. I do this so that I KNOW the gasket is NOT going to move (slip) relative to the cover.
Then I smear a THIN coeating of grease on the gasket-to-head surface and install. Retorque a few times after the first few heat cycles
Never a leak.