With this regulator there is no return from the injector body. It returns to the tank from the regulator and uses a feed from the regulator to the injector body. It is a sort of deadhead but the pressure it controlled back at the regulator. http://www.jegs.com/InstallationInst.../650-4307M.pdf
Two thing bother me.
Vapor lock and there is a slight pressure oscillation.
I think I can fix the oscillation with a vertical stand pipe connected to the injector feed line. Air trap.
I used either GM o-ring fittings or double flares on all permanent fuel connections except pump pre-filter.
You are correct on the noisy pump. Another reason to have the pump in the tank.