Well, back in about 61 and compact cars were coming on strong NASCAR decided to try a compact class. Ford showed up with 140 cube 6 cylinder water heaters in Falcons and the General brought out the 144 cube air heaters. The Mopar guys put the marine Hyper pac on a 170 cube Valiant.10.5:1 pistons, split header, a hotter ca than the Hyperpac came with, the 4 barrel long intake manifold and a bit larger 4V carb. Those Valiants that were not what could be called aerodynamic by a long shot were lapping Daytona at 128MPH. I expect the factory engineers did some magic work on the heads to aid performance. That compact class series only lasted one season as those little slants cleaned up, winning the first 7 or 8 places in every race. I don't think the General had the 4 1V carb engines for the Corvair yet, and the Ford water heaters had the cast in intake for a little 1V carb.