My suggestion about replace the bulkhead is because I can see more damage than just the burnt cavity itself, Several areas broken due the age, not related with this short.

Since you got burnt the cavities and these terminals are weak no matter what AND the original Mopar alts are poor output level at iddle I would advice consider upgrade the alt for a better output unit ( able to source around 45-50 amps iddling ). This is a tipical failure from stock disposition, poor alts what burnt these packard terminals and overheats everything around. Run the wires straight through the firewall will save the weakness of the packard terminals for the charging loads when reving up a pooor iddle output alt

If you make that you can:

-Forgett the packard terminals since we are telling to buy to replace the ones burnt... no need to buy them. Remove the old wiring from the old bulkhead clean terminals and relocate them on the new one,

-despite the new engine harness plug. If just got damaged the black wire location just forget about that. Clean the rest of terminals thought. Remove the existant black wire at engine harness.

-No need to splice two new wires into the man splice inside the cab. Just run the section between the main splice and ammeter with the same 12 gauge wire or maybe 10 straight to the solice if you want. The new wire to the alt can be attached straight to the ammeter stud. You'll be getting two terminals on black side of ammeter, the one from the main splice and the one from alt. This make just one splice job and also a straight recharging path ( if batt got discharged ) between alt and batt without need to go through the splice, Splice will suck just what needs from amm stud.

This is just if you decide to run wires straight through the firewall instead using the stock disposition. On my thread about the alt upgrade ( the first one I posted here ) I suggest the parallel path to this just because if the stock disposition is still good no need to remove them and you could use smaller gauge in parallel path ( 12 or 10 ) , BUT if the original wiring disposition is already burnt these can be removed and just use the paths out of the bulkhead using thicker wires... ( 10 or 8 )


And I still don't gett how is the fuse link wired on starter relay and I can see it in good conditions not burnt! It should burnt way before this damage was done. A fuse link takes its time to burnt, and allways gives time to some damage thought, but not like this!