Thoughts on GM alternater on 2F


Apr 13, 2003
Ridgway, CO
Do any of you guys have experience running a GM alternater on a 2F, I've heard GM's use narrower belts so I was planning on installing a Toyota pulley so I can run the wider Toyota belts. Is/are there any other tips, pros and or cons to running this alternator, the GM alt I have is way bigger (physically and in terms of capacity) than the stock 78 Toyota alt I have sitting around, so I'd much rather use it. Any thoughts and or comment regarding this are much appreciatted.
Jul 2, 2003
I'd like to hear in particular about any issues with front-to-back spacing, any wiring problems replacing an external regulator unit with an internal regulated one.

Sorry gus if I hijacked your string...
Jan 3, 2003
I replaced mine a while back with a 97 amp GM rebuilt from a local shop. The mounting was slightly different but was easily fixed with a short piece of 3/8 steel pipe as a spacer. Yes I got the shop that I bought it from to change the pully to the toyota no problem there. I went with a single wire so no need for the reg anymore though with the added amperage I did have to get a dash mount gauge that had a higher rating. I rewired mine as well from the alternator to 10 gauge just to be sure that the wire was going to be able to handle the power. The shop tolds me 12-14 would be fine but I like to be overkill on some things that don't cost anymore.v1 electrical fire in my vehicle is enough to know better from now on. The biggest problem I encountered if you can call it a problem was finding an adjustment bracket that would work. I went to the local pick a part and grabbed about 6 that I thought would work and I think the one I ended up with was for a pontiac pretty sure it was GM and it has worked fine. The alternator works awesome. I had some electrical problem before (besides the fire) with lights dimming and the stereo suck too much juice and shutting down before but now dang I can wire in all the electrical gadgets I want and I run 2 batteries now too. Hope that is a bit of help for you.

Eternal- it's only money....huh
May 2, 2003
Smaller wires such as 12 or 14 gauge are NOT fine for the GM alt. On normal times when it's only pumping a few amps it will do ok but with high beams, defroster, wipers (in other words on the worst night it could happen) such a small wire will get very hot. Do like Eternal said and use the heavy stuff.

You may wish to bypass the ammeter entirely and simply run a volt meter ... safer and you'll still know if it's charging as it should. I THINK the stock alternator was only rated at something like 37 amps which would cause no troubles ... not 3 times that much.

Connection for the 1-wire is very easy HOWEVER, unless it's been updated the "tech" section on installing one on this board is wrong. They have the #1 and #2 wires backwards which can burn out the diodes in the alternator.

Good luck

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