Dead short?

If your going to replace the harnesses, you can get the factory replacement ones and do the mad electric upgrade on the bench before you install them.
This way you retain all factory end connectors. I did this with mine.
I opened up the engine/fwd harness and took out the voltage reg, ballast wiring, and the ran a new 8 ga wire for the alt. It ran from the alt to the starter relay stud as a main buss point for power. The 2 12 ga wires that come from the ammeter were tied together then ran to that main buss point. Inside I bypassed the ammeter(not necessary now) and had it converted to a voltmeter.
I run a 100 amp 1 wire alt with ZERO ISSUES. Let me know if you have any questions.
I am a dealer for American Autowire and have done many harnesses by them including custom.