I have had to rewire the harness on my 79 LUV twice before, and have a pretty good understanging on it, your truck does not have an ECU, the distributor will either have an electronic control module in the distributor or attached to the coil, with power wires on to both the distributor, and the control module then to the coil, here are some links to wiring diagrams (
http://www.luvtruck.com/PDF/Series12.pdf ) , the wires the would need a good 12v power source constant to make you truck run are;
white and red wires from the ignitor that is mounted to the coil, these will run to the distributor, then a black wire with a red stripe to the negative side of the coil (-), and a black wire with a yellow stripe to the posative side (+)... If you cannot find any of these wires in the vacinity of the coil/distributor area, -:: ONLY DO THIS IF YOU FEEL COMFORTABLE WITH WIRING ::- peel back part of the plastic wiring harness wrap and locate the blck wires with the red and yellow stripes, use either soldier or if you dont have access to a soldiering iron then use butt connectors and splice 2 different color wires from both the yellow striped and red striped blck wires to the corresponding places on the coil/ignitor assembly, and last of all if there are no wires conected from the ignitor to the distributor either find another wiring plug from a wrecked luv/pup of the same body style, or try at your own risk to make somethign work.
-Dustin