Howdy! I just performed the easy/lazy alternator upgrade on my '64 Valiant (instructions adapted from an old post by Dan):
1. Remove old alternator.
2. Install new alternator with minor bracket mods for physical fitment. (I used this 120A Denso-style rebuilt by ACDelco)
Note: I had to shave about 3/16" off the lower mount. I was able to re-use my original upper mount with a small spacer between bracket and alternator, after swapping on a slightly shorter belt.
3. (On a '69-down vehicle) Ground one of the new alternator's two field studs, connect original field wire to the other field stud, connect original charge wire to output post.
4. Add another Big Damn Wire from the alternator charge post directly to the positive battery terminal. (I used 6 gauge because I had some handy.)

My ammeter no longer works, which is fine for now. I connected a voltmeter directly to the battery posts, and it reads the following:
~13 V after initial startup and idle.
~15 V when revving the engine in neutral
14.8-15 V after returning to idle (it stays there until you shut the engine off).

Is this a problem? Do I need to replace my voltage regulator, or check the wiring to said regulator? It's a relatively new Standard Motor Products unit and appeared to be working normally with the old alternator.

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing

That's too high. Double-check all your wiring, of course, and make sure the regulator is well grounded, but I think that regulator and that alternator aren't playing nicely. Try this regulator instead.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Another option is to add one field wire, and use this regulator
https://www.ebay.com/itm/133490869564?h ... R7am25HwYQ

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

I'll doublecheck, but I think the wiring to the VR is good. I had previously added a dedicated ground wire for it just to be sure.

I'm curious; what's the difference between the Standard VR128 and the VR101?

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing

Thanks for the rundown, Frank. Hope it gets sorted. What does that alternator weigh? Man, 120 A will feed the electrics on more than two of any of my cars...

Lou

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Home of Slant6-powered fun machines

light duty/heavy duty. That new alternator draws a whole lot more current through its field circuit than your original.

Charlie's idea is another good one.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I think I'd prefer to install the later-style voltage regulator that Charlie posted, because they seem to be cheaper and more readily available. How do I wire that one up exactly? One field wire to each of the terminals? Where does the 12V ignition circuit go? I assume it grounds through the body.

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing

My 89 diplomat had that denso 90/120 alternator with a common 70-up Mopar regulator. Factory stock.
Have also seen dodge trucks with Cummins diesels thru 96-97 with the same setup.

The wiring is very simple. But I have trouble posting pics or diagrams. The only thing that is critical is to have the 12 volt power/ign wire that goes to your present regulator connect to the proper terminal on the new regulator. The wires that go to the alternator, do not make any difference which terminal they connect to. If nobody else can post the diagram, give me a call and I can talk you thru it.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

Here's the wiring:



I am using this combination in my Dart too.

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Matt Cramer
1966 Dodge Dart turbo / EFI project

Just to add. The + ign wire is your existing wire to your existing regulator
Just add the additional wire from the new regulator to the alt field.
It does not matter which wire goes to which field terminal. It does matter which connection is on the regulator.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

Awesome. Thanks for the explanation and diagram, guys!

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing

One other thing, if you are using the adjustable regulator I referenced, the adjustment is on the back. Make sure you connect a ground wire from the regulator to ground, preferably before turning the key on.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

Another two things:

1. The '70-up regulators all look alike, but aren't. The HD adjustable one linked will have the circuitry to handle the high field current draw of a high-output alternator like this; pre-'79 Chrysler units don't, and lesser aftermarket ones might or might not.

2. The special triangular plug/socket to snap onto that regulator is this one.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I finally got around to wiring up the new voltage regulator, per the diagram Matt posted. It's seems to be working, but it still might be overcharging a little.

The battery is currently ~12.5 V with the key off. Voltage at the battery goes up to about 13.8 V after starting the engine and idling, but when you rev it up the voltage increases to about 14.5 V, and it stays there until you turn the engine off. This is definitely better than it was with the old regulator, but I'm wondering if I need to adjust the screw on the back.

What do y'all think?

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing