If you want to use an external regulator (and I did only because I had originally converted one of my 50s era vehicles in the early 80s and wanted to leave it as I had done it all those years ago. The set up gave me no troubles at all for over 30 years so I felt no need to make any real changes), you can easily do so but there are a couple of things to think about. There are two kinds of regulators for those units, mechanical and electronic. The mechanical regulators are fine to use, and they are available on ebay all the time, as long as your running an essentially stock alternator and not pulling a lot of amps. Read that if you have added halogen headlights, electric fuel pump, after market gauges, air conditioning, stereo and amps, the system will not keep up depending on the aggregate load. Now, there are some alternatives. For example, Tuff Stuff alternators sells an externally regulated 100 amp alternator that is essentially 10si guts in the earlier style alternator case. Wires up exactly as before using all the earlier wire hook up. Here is the rub. The mechanical regulator uses a point system that opens and closes to regulate the charging. If you are pulling a lot of amps with accessories, the points open and close non stop and then fails. If you have a eternally regulated system and a bunch of electronic accessories, and you can see your headlights flicker a bunch, you are in the zone. So instead of using the mechanical regulator (which you would think would be the best regulator but is not if you have some high amp draws) you use a heavy duty electronic regulator (also sold by Tuff Stuff).
Two years ago I added an electric fuel pump, stereo, and halogen headlights and relays to that vehicle. The charging system could not keep up. Went with 100 amp tuff stuff externally regulated alternator (100 amp was actually a little over kill but the cost difference was not that much) and their heavy duty electronic regulator. The only thing I had to do was re-clock the alternator to get the access to the plugs and other wiring correct. Other then that it was plug and play, works perfectly for the past two years. Its an option if you want to keep the externally regulated set up. otherwise, if you are converting from scratch, the 10si and 12 si are probably the better approach.
Last edited by Dragsix; 09/19/2018 3:49 PM.
