I saw a diagram of that fuel pump on a diesel once, I think it had a pressure regulator on top of the fuel filter so you'd feed the IP constant pressure and the excess fuel went into the return line.
Also, the carburated rabbits do have that pump, I have a '84 1.7L w/ that settup. My parts rabbit is a 1.6cis gasser and it's got a "box" bolted on the block over the lobe hole w/ some wires plugged into it.