I have a 68 Barracuda that I am having trouble with. The fuseable link melted and left me stranded the first time out this year. I am finally getting a moment to take a look at it and see what's up. I found the link melted and also a crispy connection for a large gauge wire that has replaced a wire from the alternator I believe, bypassing the factory harness wire and going to the amp gauge I assume. This wire seemed to have a poor connection causing resistance and heat, possibly causing the fuse link to melt. I replaced the bad connection and also the fuse link with 18g fuse link wire. The socket on the bulk head was crispy as usual so I made something work for now. As soon as I hooked up the battery I instantly melted the new fuseable link again, with the key off. Long story but I wonder what has been moved around by the previous owner and I want to look at a diagram of the bulk head connections so I can sort this out. Could be the connection on the gauge I assume.
Any help is appreciated.

That's what I figured. Thanks for the link.
I wonder how it happened while I was driving to be instant now.

I think I was right that the extra black wire goes to the amp gauge. If the guy who put this together bypassed the bulkhead I think he needed to run the fuseable link to the stud on the alternator, not through the bulkhead again and back. That might be the problem.

likely something moved/shifted to where it's permanently grounded/touching now. I'd start at the bulkhead fusible link in & work toward the ammeter & beyond to the splice where it T's to the lights/fuse box/ign switch. The melted insulation may help you pinpoint where it's grounded

I think I'm just going to take it apart and re do everything related to it. I want my wife to be able to drive the car without worrying that it will leave it stranded.

Check the amp gauge, a quick way to see if it is the problem is just to disconnect the 2 wires and put them together if all is ok the amp guage has shorted to the dash cluster. This happens because the studs are just insulated by a cardboard strip that crumbles and falls off, the gauge studs shift and short out against the gauge cluster.