i just ran another fuel line right down the side of my original for the return line.
i then drilled my filler tube and fish hooked a piece of metal fuel line in so it extended down in the tank and brazed it in ,out side of the car of course .i attached the new line to it using fuel injection hose that came up through the rear trunk brace so it ran down the side of the filler tube through the floor .i used a Holley fuel injection electric fuel pump just after the fuel tank ,mounted to the frame rail and attached it to the old fuel line .the front was simply hooking the fuel line and return line to the correct line ,once again using fuel injection fuel line . did it in just a few hours. this was in a Mustang for a friend,i did a Ford truck the same way ,simple and worked great.