Most of the early 80's 460 powered trucks used a ******* fuel pump setup with electric fuel pumps in the tanks. That's how mine was, and probably this one too. Look on the passenger side front of the engine; if there isn't a fuel pump bolted to the timing cover, it has electric pumps in the tanks. When I swapped mine to diesel, I had an entire donor vehicle, so I just uses the tanks out of the diesel donor. The gasser tanks had a smaller bolt pattern where the pickups/sending units bolted in, so diesel ones won't bolt in. The issues people have with this system is in the wiring; the pumps won't turn on until an oil pressure switch is tripped in the engine. But the pumps themselves seem to last really well, and put out somewhere around 5psi, which would work well on a IDI.
So there's 2 ways you could go;
You can take the fuel pumps off, and just plug some fuel line in their place with some weight hanging off of the end of them. There is already a return line in this system.
Or, with some creative wiring, you could just use the tanks with the stock fuel pumps. I would be checking on availability of new fuel pumps before I used them, but this would be a nice setup.