273 HEAD GASKETS

That's a .285" difference between the 318 and 273 standard bores. That's over 1/4". I would be looking for the smallest bore gasket I felt comfortable with running on a 273. @toolmanmike Mike, weren't the original 273 gasket bores "unround" so to speak and kinda followed the contour of the chambers, or am I imagining that? In any event, in the picture @eekvonzipper posted up there, ^^^^^, that's a TON of block deck that's now part of the chamber. You have to wonder how much effect it would have had on cylinder pressure had a smaller bore gasket been used. When I'm shopping for head gaskets, I don't look at the thinnest compressed thickness. I look at the smallest compressed volume.