Scream'n 318 ?

Solid cam, roller would be better. Good springs, roller rockers big cam. But wait, the 273's liked to rev and they did it with stock parts and none of those parts were real racy. Dual point may be. Cam was mild, 4 barrel was small exhaust was restrictive, cam was a solid flat tappet but all the 273 cams were back then. Ya and they revved to 5500 and not past 7-8 like the tales that are told. LOL

273 has a good stock head flow cfm per cid similar to a 340, 318 and 360 not so much.