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Old 02-16-2021, 11:16 PM
Billablehours Billablehours is offline
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Default Stock appearing high output alternator?

The car is a 1978 W72 4 speed. The prior owner installed a chrome high output single pole Powermaster alternator and I would like to replace it with a more stock looking natural finish high output alternator. 100 amp minimum.
Who makes one that looks closer to stock? Keeping a single pole is ok. I’m more interested in getting rid of the chrome look.

A part number would be appreciated if possible.

Here is a picture of the existing one.
Thanks
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Last edited by Billablehours; 02-16-2021 at 11:33 PM.
  #2  
Old 02-17-2021, 09:29 AM
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77 Canamman 77 Canamman is offline
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You could take the guts from your chrome unit and put them in an original natural case. Your existing unit appears to be based off from a Delco 10SI

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  #3  
Old 02-17-2021, 11:36 AM
TAKerry TAKerry is offline
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Not sure of the rating, but I got the higher rated 'stock' alt. from my local NAPA. No problems with it. 77 400 warmed up a bit automatic. I believe the cars with A/C had the higher output unit.

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Old 02-17-2021, 12:01 PM
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Higher output in 1977-78 was 63 A. 1976 was the last year of the large case 80 A. unit.

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1977 Trans Am, 400/M21 Black/Gold Bandit. 44K actual miles

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  #5  
Old 02-17-2021, 01:01 PM
shermanator2 shermanator2 is offline
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Quote:
Originally Posted by Billablehours View Post
The car is a 1978 W72 4 speed. The prior owner installed a chrome high output single pole Powermaster alternator and I would like to replace it with a more stock looking natural finish high output alternator. 100 amp minimum.
Who makes one that looks closer to stock? Keeping a single pole is ok. I’m more interested in getting rid of the chrome look.

A part number would be appreciated if possible.

Here is a picture of the existing one.
Thanks
Attachment 560948
That is a 10Si alternator. They are very generic. You can get one at any junk yard or auto parts store. They were used in all about GM cars from the early '70s to mid '80s. The only differences between them is the amperage rating and the "clocking". You can change the clocking by removing the 4 bolts and rotating the front relative the back, keeping the stator aligned as it is to the back. You can get one from a junk yard and swap the guts out of your chrome one into the dirty junk yard one, then sell you chrome housing to someone that wants to do the opposite. They only came stock up to 63 Amps I think.

It you want to buy a new one with up to 140 Amps, go here: https://alternatorparts.com/10si-alt...-and-kits.html

That being said, heat is your enemy, and more amps makes more heat. There is a model called a 12Si that came out in about 1984 or so for high amperage applications. It has much better cooling. It bolts in and wires in the same. It looks similar except for the fan is flat on the front. I think that stock they cam with up to 94 Amps.

You can get a high output one here: https://alternatorparts.com/10si-12s...ternators.html.

When you say single pole, do you mean single wire? I would not recommend this especially in you application where you apparently have high current accessories. It will under charge your battery when you have your accessories turned on. I am not sure why anyone would do this in a car that came with 3 wires to the alternator. The hot rod guys like these because they are starting with no wiring, have few accessories, are lazy and cheap, and don't understand electricity anyway.

It is important to have the voltage sensing point electrically close to the battery. The important thing being that the wire(s) between the sensing point and the battery only only carries starter current and charge/discharge current and nothing else. With a single wire alternator, the sense point is at the alternator and separated from the battery by a wire carrying all of the steady state current. The factory did not not include the extra wires because they had extra wire that they needed to use up.

As Tom V says, engineers do things for a reason.

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Old 02-17-2021, 06:20 PM
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Powermaster 7294
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Old 02-17-2021, 08:08 PM
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vertigto vertigto is offline
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Quote:
Originally Posted by OCMDGTO View Post
Powermaster 7294
Same here...from Jegs for $113.99.

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Old 02-24-2021, 07:46 PM
Don 79 TA Don 79 TA is offline
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you ok using a 12si?
10si is not gonna have enough low speed output compared to 12si, CS-144, etc...
12si was just a little bigger and i've had decent luck with them
just remember change that charging line off the alt.... if you need to pull some amps... that stock wire isn't gonna last long
also becareful getting high amp alts... some of them list them as high amps, but all they do is change the pulley to speed it up

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Old 09-26-2022, 05:33 PM
Hotrodjohn71 Hotrodjohn71 is offline
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For the guys running the powermaster 7294, being that the stock alternator had the plug on the top, 12:00 and the power master has the plug at 3:00, or towards the passenger side, did you have any problems with that new plug location with your hook up?
I get my clocking nomenclature from that mad electric website.

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Old 09-28-2022, 10:05 AM
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Skip Fix Skip Fix is offline
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My 81 TA Turbo 301 had a bigger case alternator originally.

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