[MOTORHEAD]

Steve: The wiring diagram is pretty poor in the area of the primary power distribution.
The starter motor(large)terminal should be hot whenever the batt sw is on. The rest of the electrical system is fed by a smaller red wire from that starter terminal to the fuse/relay box under the left side panel, and also to the ign sw. , so if you have voltage at the starter solenoid, but not at the fuse box or ign sw, then that wire is open. It could have broken away from the terminal where you can't see it, or it may be a bad connection at the fuse box end. I remember there was a harness connector on the pass side in the engine compartment, fwd the firewall, but don't remember if the primary power went thru it, or if it was just the fwd lights, etc., but worth checking.

Ted