On most of my farm equipment, when the OEM alternator goes, I buy a cheap [<$50 on Amazon] Delco single wire alternator, then just abandon the external regulator & alternator wiring on the equipment. I've had to do some slight mods to get pulley alignment right [a little grinding, and/or some mounting shim washers], but usually a very quick and easy job. If the Delco is spinning, and you have the ground and output hooked up to the battery+ or starter+, it's going to produce properly regulated power. If you want to get fancy, you can hook up the sense wire to the battery, and it will monitor and regulate to the voltage actually at the battery, but if that terminal isn't attached, the internal regulator will just monitor the voltage at the +output terminal, which is usually fine on farm equipment.