if that's the case, i say build it with the 273 you have (or if you can get a 318 cheap as chips). snap on some nice heads (small valve 360's), scoop up the manifold and a pair of carbs, knock on the correct valve covers to complete the look.
if you build it out with reasonable compression and cam-- say like a a 268-- then it should have plenty of yowl when you twist her tail.
273 mentioned up thread that what they built then was for a dedicated race car. if you want something that exhibits those characteristics, then by all mean copy what was done then. my feeling is that you can have something fun that's not wound up so tight as to be a pain in the *** to drive and maintain by carefully selecting more "modern" components that work together to deliver acceptable power.
but if it's just the look and sound you're after, then a thumpr with some headers will get you half way there, with the dual quads and some period correct valve covers to finish it off.
