As mentioned before, make sure the fuel pump is correct for the application. Cars/trucks with A/C (or any application where high under hood heat soak is a common occurrence) will have a fuel system designed with a return line.
The return line serves 2 basic purposes: the first is to circulate a tiny amount of fuel back to the fuel tank during normal operation. The built in fuel leak helps keep the fuel pump cool. The 2nd purpose is one most people are unaware of: the calibrated fuel leak back to the tank also bleeds off fuel pressure in the fuel line.
Imagine this situation: your driving on the highway, A/C going full blast, it’s 95* outside, you pull over for some dinner. The fuel in the fuel pump/lines continues to absorb heat, increasing the pressure in lines. Eventually, the pressure rises enough to force the needle in the carb off the seat, resulting in flooding or hard hot restart.
The tiny orifice in the return line fitting of the pump provides a place for the pump to vent the excess pressure.
The return line is another one of those “ah, cars don’t need that crap!” that people don’t understand, and actually serve a purpose.