[66pmd428]

Thanks for the reply Jon. That's part of the problem I think, because the carb is not original to the manifold. It is an aftermarket Offy manifold and the carb is a 4242s off a pontiac. If you do not have the original carb base gasket how do you know which is correct for the carb since there a couple to choose from? I guess I'm trying to figure out if I will be covering up any air passages that shouldn't be if I just use a 4 hole gasket.