if running a fuel pump with a bypass regulator will i need to run a return line back to the tank from the regulator at the carb feed line? this is a BG220PS fuel pump (220gph @ 15 psi) for a carbed motor. one of my buddies in airframes is hooking me up with some hardline for my fuel system and was just wondering if i needed some for the return all the way from the regulator or just from the bypass on the pump itself, or both.

 

From the regulator is the best place. That will keep cooler fuel going up to the engine.

There was a return line stock in your car. Has it been removed?

 

I'm with 5kid on this one. My A2000 had a built in bypass on the pump itself that I just ran a line from the pump to a bulk head fitting I installed on top of my factory tank. It worked, and I saw no pressure drops EVER, but...the fact the fuel is basically sitting in the fuel line from the rear of the car to the front waiting to get used makes it prone to absorbing heat which can cause problems. So using a regulator with a bypass is the best of both worlds, still cycling fuel and the fuel your cycling is not ust sitting in the line waiting to get used up.