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The 65 amp 2G alternator in the stock Mustang engine bay was a poor performer at best and at worst, had the potential of melting the harness plug at the alt and failing. Not good, but there is an easy solution to the problem. Swapping in a Ford 3G alternator can supply 75A, 95A, and 130A to the hard working 4x4. I chose the 130A option since the case is the same for all 3Gs as far as I could find out. They can be found under the hood of junkyard cars such as the 3.8L Taurus and I have read of Crown Vics and some trucks as well. More research can confirm this or you can just start popping hoods till ya find one. I bought a re-conditioned one from a local alternator shop that I trust so I did not have to dumpster dive this time.

The mounting is easy but there may need to be some grinding to clear the bracket on the engine. Here you can see the marked area I ground and the result. Easy as pie. The bracket is the stock 2G one that came on the 5.0 Stang.

Once that was done, the wiring was tackled. You will keep some of the stock plugs and wiring and discard some of it. There were two plugs on the 2G harness. One has 3 wires in it: GRN/RD, WT/BLK, and YL. The other plug has the heavy guage wiring to the starter solenoid (2) and the other end of the WT/BLK wire in the first plug (see pic below).

I cut the plug with the heavy charging wires and the single WT/BLK off the wires and separated the wires, discarding the heavy wires which actually join together at one point. I wanted a heavier guage wire for this. I left the three wire plug with the GRN/RD, WT/BLK, and YL alone (it plugs right into the new 3G alt) and modified the wires as follows. The WT/BLK jumpers over to the stator pin on the 3G and ends up being only a few inches long. The YL wire I trimmed a bit and then cut out the fusible link and added it to the YL wire which jumpers over to the output stud of the alt or can be run to the positive on the batt. There seems to be a debate as to which location is best. I chose the alt. The GRN/RD is listed on different diagrams as being either run to a start/run connection OR to the alt charging warning lamp. For now, I just terminated it in the wiring loom and I will see how this works out later as the Jeep does not have an idiot light for charging.

I made up a heavy guage charging wire and ran that from the alt output stud to the starter relay. Now, this wire will soon run to a 175A fuse before it hits the starter relay post and there will be a short heavy guage jumper that completes the path. I just have not been able to source a local store with the super fuse yet. The fuse will reside right next to the starter relay on the fender. I will update the pic once I get the part installed. NOTE: Do not skip the fuse or there is nothing protecting the alt from a short!

For great info on this swap, here are a couple more sites that I referenced.