The classic hot rod treatment for that coupe would be a warmed-over GMC 302, if you can find one. Back when Dad was building flathead Fords for the dirt tracks around middle Tennessee, there were lots of military-surplus 270 GMC's around, and some of them were pretty competitive. Their biggest problem was too much low-end torque causing excessive wheelspin off the turns, but if one ever got hooked up, it was hard to beat. Most of the well-modified engines around Nashville were running astronomical compression ratios, multiple carbs, and an alcohol/peroxide fuel mix, and the babbit-rod Chevy engines just wouldn't stand the strain. The full-pressure GMC's with insert bearings would take a lot more abuse.
Jerry
