Let me see if I can help. You need:
1. -8 or -6 supply and -6 return lines and all your AN fittings
2. tank adapted to accept a return line
3. EFI fuel pressure regulator (aftermarket firewall mounted)
4. your fuel rail with adapter for an aftermarket line on its supply side,and some sort of adapter at theplugged end to go to the aftermarket fuel pressure regulator (EFI) that you will need. A Steeda rail or some other custom aluminum rail would be best with AN fittings at either end.
5. a big pump adapted to your tank, or an external one. Custom fuel tank with sump of some sort with supply fitting in sump and return in top with an external pump would be trick. Supply the power to the pump with its own relay switched on with the factory relay. <font color="blue"> </font> that way you keep the inertia switch for accidents.
Now run all of your lines:
-8 or -6 to inlet side of rail, -6 out of rail to regulator, then -6 from reglator back to tank.
It is not difficult, though this is a simplified description. It does cost money though. I have well over $1000 in my Mustang's system (which can support over 100hp) and it was already a return style system