In my '53 3100 5-window I have a '69 327 block bored .30, forged flattop pistons, 70's 305 heads, edelbrock performer manifold w/600 edelbrock carb, Speedway HEI, block hugger headers with flowtech glasspack header mufflers, #42 AC plugs.
Now my problem: starts great, runs great up to 3500-4000 RPMs (don't have a tach) then spits, sputters, etc... doesn't die but have to bring it back under those RPMs to cruise. What am I missing here??????