Need help with valve covers leaking

I have a 340 with elderbrock performer heads and a rpm air gap intake with Harland sharp roller rockers. It has mopar performance valve covers that I milled down where it mates to the intake runners so it would not hit the intake when you tightened them down. They do not seem to be warped.I used thickest cork and rubber gasket I could get so they did not hit the roller rockers.I guess my question is does any one have the same set up and what gasket do you use or is there a set of covers that are for a 340 with the elderbrock intake and heads that I have