273 Exh Port MisMatch

Those were more of a heat shield than a gasket as it was just stamped tin, no gasket crush benefit on stamped tin. Many B/RB didnt get exhaust gaskets, cant comment on LA's as I never had one apart that was so original as to have the factory 'no gasket'. "rear firing" was just a phrase I used to denote a stock 65 driver side exhaust manifold as they all had that flange position. laters ones and 340 (possible here before we found the flipped gasket) never had a rear facing flange. Who new what the prior owner had on that as they get swapped out so often.