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Do I need to do anything special to convert my 1969 Cutlass S convertible 350 to an internal regulated alternator? Any suggestions on which one to buy?
The classic wiring kit I ordered from American Autowire says I need an internal regulated alternator.
If your replacing the under hood engine harness, the only thing that is needed is to remove the old regulator from the firewall. If the harness is set up for internally regulated, just install the correct alternator and plug it in.
If you need to buy a alternator, now is the perfect time for a upgrade. Ask for a alternator for a mid 80s Cadillac with the olds engine, that should be a 94 amp alternator. Replace the wire from the alternator to the horn relay with a 8 gauge. Replace the wire that goes from the horn relay to the battery with 8 gauge.
Crap, I suggested a 80s Cadillac alternator, that will work if your car has A/C with the alternator on the drivers side of the engine. If you have no A/C, you may need to reclock the alternator halves to put the alternator plug in a easy to reach location.
There's no reason to think that a higher output alternator would damage the battery, as long as it's installed correctly. Here's a good thread on upgrading your alternator:
A 1969 Cutlass came from the factory with a 10DN EXTERNALLY REGULATED alternator. You absolutely need to change the wiring to use a 12SI internally regulated alternator.
I’m doing a complete wiring upgrade using an American Autowire classic update kit. The kit says I need to use an internal regulator alternator. I just needed to know what’s the best choice of internal regulated alternator for my no A/C car.
Pretty much every alternator you'll find on RA is a 12SI, despite what they may say. I like to use AC Delco 3342305, a 94 amp unit used on mid-80s Olds 307 motors. About $78 at RA including core charge.
Thanks for the quick reply, and giving the solution. Would you take a picture to show how it looks? I am concerned with the pulley, and how it looks with that round fan vs. the stock that it was. My car is not 100% stock but is all Oldsmobile, and below is my preference, and I just can't find a 12SI that looks like this....Yet...Thanks again
not even stock but I have my preference of the older looking fan, like this one:
Thanks for the quick reply, and giving the solution. Would you take a picture to show how it looks? I am concerned with the pulley, and how it looks with that round fan vs. the stock that it was. My car is not 100% stock but is all Oldsmobile, and below is my preference, and I just can't find a 12SI that looks like this....Yet...Thanks again
not even stock but I have my preference of the older looking fan, like this one:
If the pulley and fan bothers you, you can simply swap them from your original alternator.
Fan and pulley swap from 10SI to 12SI is not a direct swap. I would not recommend putting a 10SI steel fan on a 12SI that has a baffle fan. The 12SI has a different front plate (drive end half of the alt). It has a ridge or lip that the 10SI doesn't and the steel fan would need to be spaced farther away from the openings of the alt causing reduced air draw through the alt, meaning less cooling ability.
Thanks everyone for the advice, so good to have this resource! I like the look of that alternator better than I thought I would. I am using the complete update harness from AAW and need the 12SI so this makes my decision much easier. My car will have vintage air and this should make that system work better together as well. Thanks again.
May 17th, 2022, 02:55 PM
