1980 Alternator Sizes

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Mar 1, 2009 | 06:39 PM

Smadoo

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Pro

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From: Lancaster PA

1980 Alternator Sizes

I'm replacing the belts on my 80. When I went to buy the belts, the guy at the store asked if I have the 70 amp alternator. How can I tell if I have the 70 amp?

Mar 1, 2009 | 06:57 PM

wfo76

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From: MS

Should be stamped on the alternator after alt number,

ie: 1101075 70A

Basically if you have rear window defog, you should have 70 amp,

if not probably will be 61 or 63 amp

Mar 1, 2009 | 07:05 PM

Rich N.

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Joined: Sep 2006

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From: Upper Darby PA

'80 alternator belt

Samdoo, I have ' 81s, but I believe they are the same. 70 amp is OEM, but many people change over to 100 amp when the alternator needs replacing. a PO may have changed your alternator. some of the cheaper rebuilds are not marked or painted over. an experienced parts guy should know by looking at it. the 100 amp is fatter. they are cheap enough to get the OEM belt and the next size longer. if 100 amp, it may hit the valve cover unless the belt is longer. good luck.

Mar 1, 2009 | 07:21 PM

thegazman

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From: Lewisburg WV

thegazman

What's the number on the old belt?

Mar 2, 2009 | 02:51 PM

Smadoo

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From: Lancaster PA

The current alternator was replaced by the PO(who also managed to break the lower alternator bracket

) so I didnt necesarilly want to go off of that. My car does have the rear defroster as well as the power antenna and door locks. Based on the amount of power those would draw, i assumed it would be the heavier one.

Thanks
Jim

Mar 3, 2009 | 06:55 PM

stellar

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From: Pgh. Pa.

Look at the rear of the alt. If the back of the case is flat except for the bearing it is a 63 amp. If 1/4 of the case is recessed it is the 70 amp.

Apr 27, 2009 | 02:02 PM

Grumpy 427

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From: Regina Sk Canada

I just looked at mine, and it is the 70 amp. Under what circumstances would you need to upgrade to a 100 amp? Is it required? can you make a 100 out of a 70 by changing the windings or is it a bigger case as well.

Apr 27, 2009 | 06:27 PM

stellar

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From: Pgh. Pa.

The 70 amp unit was an excellent unit. Unless there is additional electrics added from stock I would keep the 70 amp in there. Upgrades are possible in the same size case by changing windings. Depending on amount of upgrade will determine if reg and rect will need to be changed along with the bigger windings. Mark