1971 Ford Thunderbird. Just rebuilt the engine. Rebuilt carb. Having the same problem. Starts and drives fine until I accelerate heavily, (before the four barrel kicks in.) and the car stalls. Sit for a minute and pump the gas and the car starts. Guessing something from the fuel supply. Anybody can tell me what to expect when dropping the tank? Could it be the Fuel Vapor Separator needs replacing or something getting pick up in the tank? I did replace the fuel tank gas cap.