New 75amp alternator..blew fusible link.

So I put a new Powermaster 75amp alternator on replacing my stocker. I noticed a burned wire smell (faintly) for the first few times I drove and was thinking maybe my stock alt. wire was a little thin (and old) and not up to the task. Went to start it today, and it fired then popped and died. Popped the hood and had some smoke. Immediately looked at the fusible link and it was HOT so I fried it. Everything else was cool. On my 67 Dart it attaches to the left bulkhead connector of the 3 on the firewall. I disconnected it from the red lead wire and it basically slipped off the bulkhead connector, exposing a length of bare wire. My question is how does a new fusible link attach? It looks like it was part of the connector, and I'd have to replace the whole connector? Attached a picture for reference...or can I just go to NAPA and get a new link?

Also, this nagging wire has been bugging me. Again see picture, it's spliced into my ballast resistor (which doesnt seem right to me). Its a blue/yellow wire? What is this wire? It goes into my ECU connector...

Any help on these two questions much appreciated! Thanks!