I am building a 540 with efi. I have 60# injectors, an Edelbrock pro flo xt intake and fuel rails. My plan is to use a Holley HP efi computer. My question is how to set up the fuel pump with out a return line. This setup is to replace a 2001 HP 500 EFI. The HP500 uses a returnless fuel system and I would like to stay away from installing return lines as I have dual tanks with an electric cross over valve now.

Get a bypass regulator, install it at the end of the fuel rail and return it to the fill neck of the tank or I returned mine to the water separator filter housing on my 540's

I ran the Holley HP efi on my 548. I ran all Aeromotive fuel system with regulator AFTER the rails get supplied. Ran the return back to the high-flow filter head. I also had a small oil cooler setup after the pump before the rails to guard against vapor locking. Never had an issue with that and most days the fuel rails had condensation so it worked i'd venture to say.

Yes, at a minimum run it back to suction side of filter in front of pump, experts have said this doesnt work but i have ran several EFI's this way including a 1100hp blower motor, Smitty

A small ps or oil cooler with water to it after pump helps too fwiw

Ok so it should look like this block diagram.

https://www.dropbox.com/sc/661e9r82n...B1OR3nr4hGhlsa

Just a thought,buy the Imco electric fuel valve that has the supply and return to whatever tank you're on. Use 1 pump that's large enough to feed your engine with a return style regulator, forget all of the other problems you may be creating.

Eddie young sells a larger pickup with return. About the size of the fuel sender hole and it mounts in. Fixes the inadequate stock 90 for better flow and has a return nipple. We had discussed it before. You can contact him.