66 Cuda 360 questions

The other point about later model heads is with the air injector ports comes an extra long tear drop shaped exhaust port boss. This boss comes down lower than the older heads and absolutely will not allow the drivers side 273 manifold to fit. I know from trying to use 273 manifolds on a set of the #302 head castings. the passenger side will work no problem, drivers side not. However, for a 75 you probably dont have those longer port bosses. Do yourself a favor though and check the fitment of your manifolds on your heads before doing any work.