Tell me about this 273 and tranny.

My guess is that it's a 2 barrel engine that someone put a 4 barrel intake on. Single point distributor and non HP valve covers for sure. The only way to confirm a HP engine is look at the pistons or carefully measure the cam. Those are the only 2 things that are different between a 2 barrel and a 4 barrel long block. Valve covers, intake, and distributor are all easily bolted on. It's pretty easy to tell if the heads and intake are 64-64 simply by pulling a intake bolt. The 64 and 65 bolts are 5/16" and the 66 and newer are 3/8". 1/2" and 9/16 bolt heads respectively. The early intake bolt holes are also drilled at a different than the 66 and newer LA intakes so they are not interchangeable without modification. Something else we can't see is the transmission output. the 64 and 65's will have a 4 bolt flange and the 66 and newer will have a splined slip yoke. Most of you guys know this stuff but some may not.