66 mustang return fuel line

Hi,don't know where to post but need some help
I'm working on my 66 mustang don't know if I need to run a fuel return line and don't know if return line from fuel pump to tank or fuel regulator to pump.

Stock or HP EFI?

V8 or 6?

In-tank pump or on the block?

Does the fuel pump have one or more lines?

The car is not stock built 306 edelbrock heads, victor jr. Intake top with bg speed demon 650 cfm. Holley electric volumax fuel pump it 2 outlet and 1 return also holley fuel regulator has inlet and 2 outlet.stock gas tank with rear sump.my questions is the return line from fuel pump to the top of the tank. Will try to post a pic. Later

I'd add a return line.

If it is carburated, the electric pump should build to pressure and stop, if not, you can add a power to the pump pressure regulator inline, no return line. Other systems TBI, etc, would not guess. Does not have return line originally. Originally fuel pump was on the engine, mechanical.

Fuel regulator and engine bay

Opps wrong pic. Still learning

Fuel pump

Does the fuel pump receive power through a switch controlled by the oil pressure? No oil pressure, engine dies, or no oil pressure, fire source (fuel) ends. You want that to happen , trust me and believe.

The fuel pump is power by toggle switch thru +battery plan to run a relay on it shortly.i need more schooling on wiring the fuel pump the right way.