One other difference between the integrated exhaust and the 292 non-integrated is that my 2nd version '77-'78 integrated exhaust manifold appears to have the EFE valve built into the manifold itself. Whereas I believe the non-integrated 292 in SD and HD version has a separate bolt on part for the exhaust flange much like the small block Chevy passenger side manifold.
I haven't taken my top end off to really look at it yet, but that's how it appears from underneath the engine. I'm also not sure if there is an exhaust manifold difference between the '75-'76 version of the integrated head, and the '77-'78 version?
