64 barracuda 273

Well, since the LA318 was not available in '67 (not introduced until '68), it had to have been swapped into the '67 Barracuda- so it could be any year with several different combustion chamber specs. Add to that the fact that 318s never had factory 4 bbl.s until some time in the '80s, and it throws more unknowns into the mix. Is it a factory (cast iron) manifold, or an aftermarket (aluminum) manifold?
We need numbers off the heads, or at least pictures of the chambers/exhaust ports along with the same info from the intake in order to give any kind of meaningful answer.