Just run through the mechanical, use the electric to push fuel up to the mechanical pump. You will not need the electric pump just because you moved the tank, the mechanical pump will pull fuel easy enough. If you just want one, no big deal. If you use both and one fails, the other will keep you on the road, just be sure the mechanical can suck fuel through the electric. Most electric pumps will allow fuel to pass through. Always check fuel pressure at the carb once you have everything up and running. 2 - 3 psi is all you want, anymore and you can over power the floats.
For hooking one up, I would use a safety switch as GM did. Go to NAPA and order up a switch # OP6610 and connector EC428. Both are from a Chevrolet Vega. The switch is three prong oil pressure safety switch. It activates the fuel pump only when the engine sees oil pressure. If the engine dies, so does the pump. I have drawing I can e-mail you if interested, it shows how to wire pumps. ( I don't have a way to post it )
The third prong on the switch is for low oil pressure dash light if your truck has one. I also use this post for hooking up a primer button, so you can fill the fuel system before starting with a push button. It comes in handy if the truck sets for long periods.
Joe
