Thanks guys. No porting done, so hopefully stock heads are thick enough, although a crack did occur to me. I did look at the underside of the manifold for cracks and didn't see any, but that certainly doesn't mean there isn't one. It did look a bit "wet" looking up the manifold intake runner.

I wonder how they check aluminum for cracks.....I doubt magnafluxing would work..... And it's not a Ford manifold....it's a 2x4 360Deg Offenhauser, so "readily available" is not likely. Bad port matching anyway......would try to find a different 2x4 manifold....mind you, then there's that epoxy idea.....

anyways, you guys are right....I need to do a close inspection for manifold cracks.......thank-you