Hi,
I recently removed a 12v alternator from my HJ. I wanted the engine compartment to look more stock than the alternator allowed. What also urged me along was the car had already been changed to 12v and neg grd, and a 12v electric fuel pump installed. And, of course, all of the lights changed. I purchased 12v field coils for my 6v gen (came with the car) and bought the brackets and now it looks stock. However, that is only half of the problem. Identifying a correct 12v regulator is becoming a challenge. I would very much like to hear from anyone who has found a regulator for the 12v generator neg grd conversion. Back to your inquiry chrysleralmighty, Kaiser Willys Auto Supply, LLC sells a 6v to 12v alternator conversion that looks like what I removed from my car. I would gladly sell you what I removed from my car, but I don't have any instructions, just some pics of what it looked like before removal.
Good luck,
Shel