Seems to me It's better to accurately trouble shoot the problem, then replace the defective part.

Try this: run the car a bit, then shut it off. Crack line at the carb, fuel should squirt a bit. If it does, then you know three things: pump works, pump check valve and float valve hold pressure ( at least short term ).

I'm going to assume you do get a squirt. So next, to figure out if the fuel is leaking past the pump check valve. Start the car to pressurize the fuel line, then shut it down. Disconnect the fuel line feeding the pump and plug it. Clamp a small length of fuel hose to the pump, and puttthe other end in a bowl on the floor, let it sit overnight. If you have fuel in the bowl the next morning, then the problem is in the pump.