[BobbyK]

When I converted to fuel injection I ran the return line down the drivers rail.
There are no unused ports on the tank. I tried using the small vent line that runs beside the large fuel fill tube but that cause fuel filling issue's.

I ended up making a "T" that went inline on the fuel fill hose. Worked great.
It's just a piece of tubing with a barbed fitting screwed into it. I put JB weld around the barbed fitting just in case. It's never leaked...and it was cheap.

I think Jeg's sells something similar though.