[jciwolf]

I have a 1970 gto with charging and starting problems. The alternator is a 37amp ac delco rebuilt with an 800 amp battery. Starter is a Jegs 3hp,with a 10 gauge wire from the alternator to the starter where it connects with the battery wire at 4awg wire. The system will not charge the battery past 10volts and this does not allow the motor to start unless I add my charging unit to add 200 more amps. Do I get a higher amp alternator and higher gauge wire from the alternator or both. I am thinking 75 amp alternator to begin with. Any help would be appreciated.

[64speed]

I have never heard of a 37 Amp alternator. If that’s truly what you have then it is NOT charging the battery and running everything. I don’t like one wire alternators but there are tons of hi amp three wire alternators out there. Just get the external to internal voltage regulator adapter and go to a parts store and get an alternator for a late 70s 3500 GMC truck with a 350 or a 454. If you want to dress it up and get a chrome alternator there are still plenty of three wires made just search amazon. There really is nothing wrong with a one wire though. I just like using all my factory wiring and have my battery light work. If you go with a 1 wire the sky is the limit both in price and amps

[Geoff]

Unless you have added electrical accessories that draw more than 37 amps, then the alt should charge the battery assuming wiring is correct.
I would suspect the voltage reg.

[OG68]

Originally Posted by Geoff

Unless you have added electrical accessories that draw more than 37 amps, then the alt should charge the battery assuming wiring is correct.
I would suspect the voltage reg.

X2. Assuming the wiring is correct
Suggest Wells VR15 electronic regulator available at Auto-Zone.

37 Amp alternator was the standard alternator unless the car has air conditioning which came with a 55-61 Amp.

[johnta1]

The original charging system had a regulator, was the alternator correct for it?


Check/test alternator again?

I'd check/change the regulator?
(alternator should put out 12 volts all the time, amps vary)


Battery good still?
Battery if charged should start the engine a few times without the alternator.