Interesting question, Since Patrick's "GMC Fentons" are really Chev 235 with the holes for the mounting studs elongated. A 270 exhaust manifold will probably fit a 235 with some work, but not sure if the ports would be an exact match, or whether the alignment rings will still be usable...probably not. Also doubtful if the Chev header pipe would mate up to the 270 exhaust flange.
