What are you using?
overall I've had great luck with stock steel ones, unless they have been tweaked and stretched around the bolt holes from overtightening... then you'll never get them to stop leaking. Look at the mounting surface of what you're using and see if it's straight and flat, if it's not, find a new set.
I had horrible luck with a cast aluminum set until I realized they had a lip that was getting hung up on the intake runner causing them to not seal against the gasket completely.
I typically look for cork gaskets, usually felpro, but I think summit has "double thick" cork ones avail from somebody too. I've used those on a car that I had the VC's off frequently for valve adjusts with good luck resealing.
Hope this helps.
