72Shark

I'm going to order a new chrome alternator for my '72, but am stuck on the amp question. I gather that I have a 63 amp originally?? Should I up the amperage or will this unnecessary or will it cause problems?? Also, what's all this "one wire" information out there?? I have a "hot" wire, a ground, and a two wire "plug in" on the alternator. What does "one-wire" mean, and should I go this route??

BSeery

The "one wire" gets rid of that plug. You have the hot lead, the ground is through the bracket and you don't have the 2 wire plug anymore. It's usually a concern for street rodders who are looking to clean up the engine compartment as much as possible.

As far as amps, get a unit that is between 60 and 100 amps. Just make sure to get a quality unit that has a good warranty. If you go to 100 amps or higher, make sure that you have either 1 very good heavy duty wire from the output of the alternator or better yet 2 good heavy wires from the alternator to the starter terminal.

No use pushing out all those amps if the wire you are using can't take them.

OHSIXX

Mine is Tuff Stuff 80 Amps. I think it was $99.99 from Jegs.

72Shark

Can I go to one wire without messing anything up...like my new volt gauge. In other words, eliminating the 2-wire plug won't mess up my volt gauge...right??

rob75383

I was going to warn you about the stock gauge, until you mentioned your "new" voltmeter.
Is it a true voltmeter, or is it an ammeter??

I found out the hard way that you can't have an alternator over about 60amps without burning out the ammeter gauge. After I blew the old alternator, and the ammeter didn't work anymore, I thought the ammeter blew with the old alternator, not from being fried from my new 84amp alternator.

As far as the one wire messing up you gauge, in my opinion, it shouldn't be an issue... but I can't guarantee it, so ask the other guys here.

zwede

I have a 80A alternator and the stock ammeter is fine.

Actually, rather than looking at the max output you really should look at the charging curve. A 10SI Delco (which is probably what you're looking at) has very poor low rpm charging abilities. I upgraded to the 12SI which was factory on late C3's. Only change is the housing is 1/2" wider so I had to slightly bend a bracket. The 12SI charges much better at low rpm.

I have EFI, a decent stereo, stronger headlights, spal electric fans (25A) and even with everything on at once the ammeter still stays on the positive side at idle.

I don't recommend one-wire alternators. The wires you are getting rid of are what is known as the reference wire and the exciter wire. The ref is telling the alternator how charged the battery is, and the exciter wires makes it come on when you start the engine.

A one-wire alternator has to be revved before it will start charging and they will not do a very good job at keeping the battery charged (either under or overcharged). Leave the one-wires to the street rod crowd.

Remember, if GM could have saved 2 wires they would have.

greg454

:iagree: :yesnod:

Gator81

Not a '72 expert, but looking at the books, it appears that the stocker is 42 amps w/o AC, or 61 amp with AC. I know that the stocker for my '81, with AC, is 63 amp. When I needed a replacement and a properly clocked 63 amp unit wasn't available, I picked up a 100 amper because it was available with correct clocking and I was in a hurry. That was a mistake, had various problems with gauges, with wiring, with drag on the engine at idle, etc. Eventually got a correct 63 amp unit and have had no more problems. This may be meaningless for your application... just my $.02... :)

daves80

i used a unit from a 85 camaro - higher output (around 90) - same size and shape exept for the plastic fan - worked great and was only 34.00 from napa - dave


[Modified by daves80, 5:44 PM 2/7/2003]

OHSIXX

Check out Jegs PN 908-7127RA. I am almost certain that is the one I have with no problems.


[Modified by OHSIXX, 3:05 PM 2/7/2003]


[Modified by OHSIXX, 3:06 PM 2/7/2003]

wallyknoch

72`s still have a remote regulator. 63 amp would be satisfactory. You will never use it all unless the car is air conditioned. One wire alts have the regulator built in as from 73 on... :thumbs: