65 273 Intake manifold

Update on this SP2P 318 manifold. I appreciate all the feed back I have received about installing this manifold. I have looked the manifold over very closely and have found it to be all original with no modifications as to bolt holes and such. This is a numbers matching car built on 9/17/1964. To my knowledge the heads are original to the engine. Today I test fitted the manifold on my early 273. Fortunately, the manifold fits perfectly with all bolts at the proper angle corresponding with the manifold. I'm not sure but, could I have an Edelbrock manifold made for the 273 or possibly later heads? If the heads are from a 318, is there a way to find out? Thanks again.