Do I need to install a fuse on a altenator wire?

That’s why I said replace.....

FYI, I am doing some rewiring in my Magnum. I have found just what the OP has found. I also eliminated a few pounds of wire. No more “Leanburn Ignition” and emission controls, relay and etc.... I’m also going to extend the wiring to hide it some to clean up the engine bay.

What I have found is the wrapped wire was pretty good. The exposed sections at the connections were brittle & often oil soaked.

There is no need to add extra wiring unless your adding something to the car that needs a heavier gauge wire than what is there already. If it runs, leave it be. Just replace what’s bad. Use the same gauge wire or thicker wire. All will be good.