So, quick update: we swapped in a TH350 with a 2000-ish converter, power steering to manual conversion, HEI distributor, rebuilt 1406 Edelbrock carb with electric choke, headers and dual exhaust, ditched the cruise control and A/C so no more computer. Otherwise it’s a stock 307 1986 Regal. Actually ran pretty good! Next,we swapped in a set of 373 gears into the stock 7.5 rear end. Boy howdy, did that wake up the old girl! Does a one wheel peel like crazy! However, the RPM’s come up really quick and first gear is almost non-existent. I have not gotten a tach installed yet (I know...). My question: in high gear at a steady RPM the engine has a “flutter”. Could this be valve float?