Are you talking about the end valley gaskets, facing the firewall and radiator? If those are going out and blowing oil then your pcv system needs help. The problem is the forced induction- you are getting more blowby than the engine would normally aspirated. You probably need a pcv valve and breather filter in each valve cover. You will need a check valve between the PCV valves and the vacuum source that you hook it to so it doesn't pressurize the crankcase when the engine is under boost. If you have a drawthrough setup put the pcv intake between the carb and the blower. That should help.

Paint & Body Shop moderator
A lone amateur built the Ark. A large group of professionals built the Titanic.