That model still has the disintegrating wiring insulation. If the fire was down inside the loom, the rest of the wires are cooked too. The best solution would be to replace the whole wiring loom (harness) with a good used one. Try Dan Barton's web site. You could also make up your own harness but it would be slow work.

When I was 18 and coming home from college at 1:30 in the morning the wiring under the dash in my '37 Chev caught on fire. It was on a curve, winter, Minnesota snow and ice, no lights, deep ditches on the side and miles from home. For some odd reason I still have a very vivid memory of that night even a half-century later. I had to put a whole new wiring harness in from headlight to taillight! Good luck on your repair.