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Alternator requirements w/ac

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304-dude View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Mar/31/2023 at 6:14pm
Originally posted by JD JD wrote:

"The alternator Trader lists does fit and work well."

This alternator that Trader listed will fit the AMC brackets without any cutting or modifications?



I thought so, even Billd mentioned it is better than SI series, but i never knew it fit Motorola brackets. I know later 80s with the SI the brackets changed to accommodate.
71 Javelin SST body
390 69 crank, 70 block & heads
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JD Quote  Post ReplyReply Direct Link To This Post Posted: Mar/31/2023 at 6:25pm
Yea i had seen where people cut the aluminium shorter to get the GM alt. to fit the AMC bracket but if this one would fit without chopping on it that would be a big plus. Maybe Trader and Mopar_ guy will clarify.

Edited by JD - Mar/31/2023 at 6:30pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bigbad69 Quote  Post ReplyReply Direct Link To This Post Posted: Mar/31/2023 at 6:31pm
If the alternator don't fit, you must acquit. Smile

Better to mod' the bracket than the alternator. If it goes dead, and you're a long way from home, a parts store alternator will get you home. Hogging out an alternator in a parking lot is no fun.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote JD Quote  Post ReplyReply Direct Link To This Post Posted: Mar/31/2023 at 7:16pm
Your right for sure BigBad69, modifying the bracket would be the way to go if you had to make it fit.Like you say do it once and you'll never get stranded hacking on an alternator and instantly voiding the warranty.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 6PakBee Quote  Post ReplyReply Direct Link To This Post Posted: Mar/31/2023 at 8:43pm
Any time I read these posts I shudder at the thought of a stock wiring harness designed for ~60 amps maximum suddenly having about twice that much current impressed on it.  If I ever upgraded an alternator to handle EFI or electric fans, I'd upgrade some of the harness also.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mopar_guy Quote  Post ReplyReply Direct Link To This Post Posted: Mar/31/2023 at 9:08pm
Originally posted by JD JD wrote:

Yea i had seen where people cut the aluminium shorter to get the GM alt. to fit the AMC bracket but if this one would fit without chopping on it that would be a big plus. Maybe Trader and Mopar_ guy will clarify.

Yes, that's the common thing to do but not practical IMO. I would modify the brackets so it fits without modifying the alternator so it can be swapped out easily. I used a Motorcraft alternator before which worked nice that was easy to do. https://theamcforum.com/forum/motorcraft-alternator-upgrade_topic39960_post363799.html?
If you do put a high amp alternator on, definitely hook it to the battery with a proper size fuse and wire. Do not run it thru a factory amp meter or you can burn it out and possibly cause a fire.

"Hemilina" My 1973, 5.7 Hemi swapped Javelin
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mopar_guy Quote  Post ReplyReply Direct Link To This Post Posted: Mar/31/2023 at 9:14pm
Originally posted by 6PakBee 6PakBee wrote:

Any time I read these posts I shudder at the thought of a stock wiring harness designed for ~60 amps maximum suddenly having about twice that much current impressed on it.  If I ever upgraded an alternator to handle EFI or electric fans, I'd upgrade some of the harness also.

You don't really need to change the factory harness, just run the alternator output to the battery or the battery side of the solenoid with a fuse. Depending on how the car is wired, either dead end it or take the original wire and do the same with it. This way if the alternator is putting out it's max, it won't damage the wiring.

"Hemilina" My 1973, 5.7 Hemi swapped Javelin
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Mar/31/2023 at 9:17pm
The CS130 or SI will bolt into the same location as the Motorola. You may have to make some spacers and shorten the rear bracket, depending on the model/year of AMC/Jeep engine your bolting to.
As for adding circuits, yes they need separate wiring and fusing. The wire gauge for the alternator to the battery should be increased, only real change needed, #4 is fine for that short of run at 100 AMPs.
The rest of the harness is fine as the factory circuits will only draw what they always have, nothing changes as long as you don't piggy back on factory circuits.
IMO don't change the factory harness circuits, add new circuits separately with separate fuses. Small under hood fuse panel for your new circuits in this case would be perfect.
The alternator will only produce what is required by the circuits connected. It's not pumping out 100 AMPs all the time and likely never would unless the battery is drained and then the battery is taking the load, which it is designed to do. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 6PakBee Quote  Post ReplyReply Direct Link To This Post Posted: Apr/01/2023 at 10:15am
Originally posted by Mopar_guy Mopar_guy wrote:

Originally posted by 6PakBee 6PakBee wrote:

Any time I read these posts I shudder at the thought of a stock wiring harness designed for ~60 amps maximum suddenly having about twice that much current impressed on it.  If I ever upgraded an alternator to handle EFI or electric fans, I'd upgrade some of the harness also.

You don't really need to change the factory harness, just run the alternator output to the battery or the battery side of the solenoid with a fuse. Depending on how the car is wired, either dead end it or take the original wire and do the same with it. This way if the alternator is putting out it's max, it won't damage the wiring.


I can't disagree with you.  But if you added a big stereo, EFT, electric fans, etc. I could easily see an additional wiring harness to support and control the additional load.  My whole point was simply to have people consider ALL the ramifications of a larger alternator in that it may not be plug and play.
Roger Gazur
1969 'B' Scheme SC/Rambler
1970 RWB 4-spd Machine
1970 Sonic Silver auto AMX

All project cars.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mopar_guy Quote  Post ReplyReply Direct Link To This Post Posted: Apr/01/2023 at 10:34am
Originally posted by 6PakBee 6PakBee wrote:

Originally posted by Mopar_guy Mopar_guy wrote:

Originally posted by 6PakBee 6PakBee wrote:

Any time I read these posts I shudder at the thought of a stock wiring harness designed for ~60 amps maximum suddenly having about twice that much current impressed on it.  If I ever upgraded an alternator to handle EFI or electric fans, I'd upgrade some of the harness also.

You don't really need to change the factory harness, just run the alternator output to the battery or the battery side of the solenoid with a fuse. Depending on how the car is wired, either dead end it or take the original wire and do the same with it. This way if the alternator is putting out it's max, it won't damage the wiring.


I can't disagree with you.  But if you added a big stereo, EFT, electric fans, etc. I could easily see an additional wiring harness to support and control the additional load.  My whole point was simply to have people consider ALL the ramifications of a larger alternator in that it may not be plug and play.

Oh I agree but I took it as just the alternator swap you were referring to.

"Hemilina" My 1973, 5.7 Hemi swapped Javelin
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