Low Fuel Pressure in LS1 Transplant! PLEASE HELP

First off, I would like to say that I have read a few of the "low fuel pressure" threads using the search feature.

I am running an ls1 in a 1964 Chevelle SS, using the Ricks Hot Rod Shop Tank setup. My first issue was I didnt have enough voltage and amps at the pump. I am now way above what the pump requires with 14.7 volts at the pump, yet only getting 50psi fuel pressure at the fuel rail shrader valve. I am using the corvette style regulator/filter combo. I was told by Ricks hot rod shop, that the pump in this tank is an AC DELCO EP381 (25163473), which is the fuel pump in all ls1 equppied f-dodies. Yet, I am still having low fuel pressure, and the pressure fluctuates with any amount of throttle given.

I have -6an braided fuel line all the way from the tank to the fuel rail. No visible fuel leaks.

With the fuel pressure tester on the shrader valve, and the key on, but car not running, I get about 50-52psi. As minutes go bye, the pressure drops very slowly. I checked for a leaky injector, and none are present.

Any help would be great guys, Im starting to go crazy...

I'd try to get another regulator to swap in.

I'd try to get another regulator to swap in.

Second AC Delco Filter/Regulator combo I have tried.

I read about those tanks on Year One's site. It look slike a pretty slick setup, but it doesn't say anything about regulators. The stock ls1 f-bodies used an in-tank regulator. Are you sure the Corvette setup you have is actually a regulator? I am not a vette guy, so don't be alarmed if that is a stupid question. Is it vaccum referenced? If it is rising rate, then you should be OK with 50 at idle.

-Geoff