Then the easy way of correcting the alternator plug would be to place a blade terminal over the unused blade on the alternator, with no wire, and just insulation. Do the charge wire with brass, double crimp as pictured above, and it is like OEM.
I like the battery cable lugs on the engine...
I like those brass terminals, above. They crimp for conductivity and they crimp for strength on the insulation. So, Matt, he could just install one wire and leave the other slot open? Or is there something about the alternator that needs update in the harness side of things?
I'd just run...
One wire is hot, it would be the ignition wire that wasn't on the regulator. The other two go to the alternator, Field and Earth/ground. I'm just interpreting the diagram posted by Matt.
These wires would be easy to cover with shrink wrap and electrical tape, zip tie it out of the way...
I don't know. However, it would be reasonable, as the truck runs as suggested in post #4.
Can't an internally-regulated unit be wired to work in this situation?