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High running voltage levels on 66 and 67


FBBO Gold Member
FBBO Gold Member
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Jan 28, 2012
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I have a 67 GTX and a 66 Satellite, both with under dash voltage gauges. Both cars have rebuilt alternators, new solid state regulators, and the 66 has complete new wiring harness. The 67 has all original harness but no Bubba work on it and everything works. Both cars run over towards 15 volts. I had the 66 out this morning and when I returned I decided to check it with my multi meter so I hooked it up to the battery and got 12.6 or 7 volts. Started the car jump and the voltage rose to 14.6-14.7 at idle and low rpm. Based on this I think the 67 is about the same.

The 67 has a store bought, rebuilt single field alternator and the 66 has a quality rebuilt/restored single field alt. I bought from a forum member. No high amp or modified alternators. VRs are solid state I probably found on eBay or a Mopar parts house. To me these regulators are demanding too high of voltage of the alternator.

Does anyone have knowledge of a reliable, stock appearing voltage regulator that I can count on to put out a steady 13.8 - 14 volts max?

The only good think is I don’t have any problems with dim headlights or the AC in the 67 pulling the voltage down on either car.

I'll put a meter on mine this weekend or 1st of the week.

The alternator is / was an nos Mopar piece 20 years ago. I put an nos points type VR on it over 2 years ago ( to replace an ugly electronic version ) . And Ive not noticed any high voltage issues ever
I will add, I went thru 3 or 4 of the aftermkt electronic versions when I did the 67 Coronet before I got one I liked where it ran voltage wise
That’s kind of what I’m afraid I may be facing. The one on the 66 and the one on the 67 were purchased about 4-5 years apart probably, but they appear to both be putting out the same high voltage.
The problem is that all the current reproduced electronic voltage regulators for 1969 and older cars made nowadays regulate between 14.8 - 15.2 volts. I went through this same thing over the past few years. I didn't like that high of voltage and taking a chance of boiling a battery or burning gauges. I finally said screw it and converted over to the internally regulated Denso style alternator.
PS, I might have an extra NOS points type if you want to try it.


I installed this one when I put in my new alternator. Solid State VR runs at 14.5. But I didn't care about 100% OE correct looks.
The link shows not in stock. It is a bit non-stock looking. I wonder if an old cover would fit over one?

Give thought, if you're running an Odyssey battery in an old case they like a 14.7 volt charging level.
And every single one of them with the metal case regulates at too high of voltage, just what the op and everybody else doesn't want......

Hmm, never heard of that problem specifically with the solid state ones. The re-popped mechanicals, yes.

I found this on eBay. It looks like the one from Discount Starter and Generator from outward appearances. Correct restoration look is a bit of a stretch.

Mopar Voltage Regulator Electronic Solid State & Correct Restoration Look - New | eBay

Yes, that would be a similar one to what I have. And you are right, not restoration look by any means.
Give thought, if you're running an Odyssey battery in an old case they like a 14.7 volt charging level.
No, I’m running regular Interstate batteries in them. Haven‘t experienced any problems with the high voltage as of yet - dim headlights aren‘t an issue for sure. But these cars are pretty stock still running the old alternator gages, wet cell batteries and in the case of the GTX, the original wiring harness and it’s a worry. That just seems to be well above normal system voltage.
Voltage isn't a problem. Amps are....

That said, I'm betting the old radio doesn't appreciate 14+ volts. If you're running an electronic regulator for gauges then should be no issues.
Just after starting the car, 14.7 volts at idle/low rpm would not worry me.
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