I have run Geronimo with an electric pump back by the tank for 32 years. I am running a holley 5 PSI pump with no reg, with 1 filter before the pump and one before the carb and have no issues. He is also an 1980 D-50 sport with 2.6 and a 5 spd manual. When getting a pump the higher the flow rate the better - weber carbs are more flow rate than pressure sensitive to a point.