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Old 08-27-2011, 07:57 AM
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Want a 94 Amp 12SI Alternator For A '71 SBC

I have been doing research and have found that the 12SI came in several amp capacities. We are upgrading our '71 Monte Carlo's alternator and have decided on the 94 amp 12SI.
But I do not know the exact year/make/model of an '83 or later year that used this alternator, which would also bolt right on to the existing 350 SBC alternator mounting we have.
Can anyone help me out?
jogasz28
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Old 08-27-2011, 11:52 AM
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Alt

Quote:
Originally Posted by jogasz28
I have been doing research and have found that the 12SI came in several amp capacities. We are upgrading our '71 Monte Carlo's alternator and have decided on the 94 amp 12SI.
But I do not know the exact year/make/model of an '83 or later year that used this alternator, which would also bolt right on to the existing 350 SBC alternator mounting we have.
Can anyone help me out?
jogasz28
As most alt. brackets are adjustable on one end, I don't think you have to worry about year. If you are, take yours down with you when you get yours. If ordering on phone ask the sales person if year makes a differance. I have an older 350, and put a bigger one on I just ordered it and year never came up.

Bob
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Old 08-27-2011, 12:00 PM
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Quote:
Originally Posted by 35terraplane
As most alt. brackets are adjustable on one end, I don't think you have to worry about year. If you are, take yours down with you when you get yours. If ordering on phone ask the sales person if year makes a differance. I have an older 350, and put a bigger one on I just ordered it and year never came up.

Bob
Appreciate the reply.
But my research indicates the 12SI came in in several amp ratings.
How do I make sure I'm getting the 94 amp 12SI alternator?
jogasz28
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Old 08-27-2011, 12:14 PM
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I just found this Delco info from:

http://bobsgarage.110mb.com/gm/gm_2.html

3:00 o'clock, Delco #1101308 / 321-266 / 7294-3
For a 84 Chevy Camaro HiPo 5.0L (305G) 94amp

I don't know what the /321-266/7294-3 means.

Opinions?
jogasz28
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Old 08-27-2011, 12:25 PM
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I thought the 10si and 12si were identical as far as mounting goes. The 12si had better cooling ability because of the fan pulley type and a little lip on the front of the case that directed air through it more precisely. I could be wrong though

Ive also read numerous articles through the years that "claim" that alternators bought from an autoparts store are NOT guaranteed to have the correct output as far as amps goes. Unless you can test them yourself you have no exact output rating on those. Again, that might be someones pissed off opinion but I read that 3 times over the years regarding rebuilt alts.

You could just go with an aftermarket alt like Powermaster or other seller and they have 100amp and up. Direct replacement with 3 wire connections that can also be used as 1 wire (I dont recommend using 1 wire though). They all use the original 10si housing, chrome it, and install their own internals. If you can find a 12si aftermarket then thats even better I suppose.
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Old 08-27-2011, 12:45 PM
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The 7294-3 is the Lester Number, which is a general reference number used for types of alternators. The -3 references the 3 o'clock position for the location of the two-wire plug, so you may also have the 7294 parts numbers with -6, -9, etc. You might find this page useful http://www.extreme4wheelin.com/tech/...ators/tech.htm

I bought a 94 amp 7294-3 alternator with a single groove pulley for my '75 SBC, where the alternator is mounted up high on the passenger side. I tried first using the reference for the 84 Camaro, but in a couple of cases the store parts number did not seem to match what I wanted. However, I did find this alternator at Advance Auto Parts
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Alternator---94-Amps-Worldwide_5210283-P_11_R|GRPALTSAMS_539077066____

It may be easier to look up parts numbers and verify that they are the right Lester number. The only catch is that the 7294-3 alternator is available in both v-pulley and serpentine versions, so get one with the right pulley. You will also find that the threads for the tension bolt are metric, so you can't reuse your old bolt. The pivot bolt fits fine because it threads into the block. I also upgraded from the stock 10 gauge charge wire to an 8 gauge wire with a 12 gauge fusible link.

Bruce
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Old 08-27-2011, 12:48 PM
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After talking to Mark Hamilton from MadElectrical.com, I will probably go with the Powermaster. Mark had high praise for the quality of the Powermaster alternator. He stressed how they use high quality components instead of offshore knockoffs resulting in an extremely reliable alternator.
I was just trying to see if I could find a Delco alternator that would work.
jogasz28
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Old 08-27-2011, 03:08 PM
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If youre going to upgrade, a few dollars more can get the powermaster and at least you know what you got

I just installed a powermaster a month ago and it was like night and day from the stock alt I had on my 86 monte. Even at idle with everything running its outputting more and I think it wasnt much of a price difference for the powermaster. I had to remove the V belt pulley and install the serpentine and that was about it.
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