392 walbro electric fuel pump question

The regulator design will determine if that diagram is useful. If it's an EFI regulator it's just fine providing the injectors, regulator, and return line are sized properly. The injectors are the real "open/closed" valves in an EFI.
Just my opinion but in a carbureted system and running a pump with that much volume I would not run it like that diagram shows. To me, as drawn, the carb's needles are exposed to full flow and the floats may not be enough to close them if it can go 60psi or more. I'd run the regulator before the carb and a return line the same size as the feed line. Because you are limiting the pumps volume so much at idle you amy want to look into a fuel pump management unit to keep it from overheating during long idle or light throttle running.