I used 6 ga wire running through a big fuse to the battery side of the starter solenoid.  All original wiring to the regulator got removed. 
I use a volt gauge. Much more informative than an ammeter.

I understand the regulator gets removed but can I just leave the plug there or do I have to remove it from the harness?   I’m not using a ford alternator, it’s a GM unit from CVF so I’m not sure how similar or different the two are.  As I mentioned before, electrical work is my weakness skill set. 

Do I use the factory electrical connections to connect to the aftermarket autometer alternator gauge or do I have to connect it directly to the alternator?   I’m not sure if the voltage regulator being remove affects this or not.   In theory it sounds like I can leave the voltage regulator connector in place and use the dash connections for the aftermarket alt gauge.  I have read that if I had the alt light then that would require extra work to get a gauge to work in its place.

Here’s the alternator wiring my I bought per CVF.

BobE wrote:

The wiring shown will work however, there isn't shown a provision for a voltmeter, ammeter, or charge light circuit.
So, is your Mustang a 65 or 66 model? (as the wiring is slightly different due to the 5-gauge panel in the 66)
Are you planning to install a voltmeter, ammeter, or charge light indicator?
My opinion: I'd use a voltmeter and maybe install a charge light indicator.  I like a charge light indicator because if the alternator fails, the light comes on right away.  Without it, if the alternator fails, the battery will carry the load, the voltage reading will slowly decay and one may not notice the gauge until the car shuts down.  
If you let me know the answers to the above questions, I can send you a hand sketched wiring diagram.  Let me your email address also. 
 

 
It’s a 66 mustang and I plan on installing all autometer gauges.  One of my questions is asking about wiring up a gauge and if I just use the stick connections or not.   I’m suspecting that with the voltage regulator out then using the stock connections at the instrument panel. 

Now I’m not sure how to even begin to wire up both a light and gauge.

Rudi wrote:

The Autometer gauges use dedicated senders for their operation, I doubt they willl work with O/E senders.
I’m not familiar with 66 wiring but the wires themselves might be compatible for connecting senders to gauges,I’d be tempted to run all new wires to eliminate any old wire issues.
When I did a complete AAW conversion I put in  new Autometer gauges.
https://imgur.com/Qnp9TF8

 
I’m only questioning the alternator gauge hook up.  Not the other gauges.   


All my wiring is new.   Dash harness is the upgraded Scott Drake with modern fuses.

BobE wrote:

Ok, it is a 66 model and you're installing Autometer gauges.  You can use the OEM wiring to these gauges.  If you're using the original wires, make sure they are in good shape. 
Still need to know if your going to use a voltmeter or ammeter.  I suggest the voltmeter. 
Note that the selection of an ammeter depends on the rated output of the alternator. 
A charge light circuit would be indepenent of either gauge you use. 

 
Pretty sure I put voltmeter in my cart but will double check.  I like the idea of adding the light.   It will take some research and effort but I’m sure I can work through it with the help from others more experienced than me.

Sending pm.

So I still don’t know what to do with the plug for the voltage regulator, do I leave it alone and everything will still work like it should?  I keep thinking that the charging circuit will be interrupted with the voltage regulator gone meaning will the dash wires still provide the voltage reading I need for the gauge?

rpm wrote:

Fold over the unused ends, tape or wire your them together, and put a wire look over them.

 
Then I’ll cut the connector off and seal the ends up.  I’ll use shrink wrap.

wsinsle wrote:

RTM wrote:

Sending pm.

So I still don’t know what to do with the plug for the voltage regulator, do I leave it alone and everything will still work like it should? I keep thinking that the charging circuit will be interrupted with the voltage regulator gone meaning will the dash wires still provide the voltage reading I need for the gauge?

Just unplug the voltage regulator, as BE explained the 1 wire GM alternator has an internal regulator. All gauges will work except the Amp meter. You will need to find a wire that is hot only when the key is on to operate your new volt meter. I don't think a light will work with a 1 wire GM, Ford had a special output for that. I may be wrong, don't remember how BB made a LED hook up.

 
The dash harness has extra fused hot wires I may be able to use.

For my voltmeter's 12v source, I used the wire going to the gauge's CVU.  It is right there on the gauge panel, very convenient.  I grounded the voltmeter to the gauge panel ground wire. 

rpm wrote:

I think I remember reading that an idiot light won't work with a 1 wire alternator.

 
I think I read that it requires some special wiring to get it to work but that’s all I recall.

Like BobE said in post #19, you should only need the old CVU wire to the voltmeter, and a ground from it. Not the red wire.
No further need for the CVU.
 

RTM - If you use the red wire from the solenoid, power to the voltmeter will always be ‘on’.  While the current draw of the voltmeter is quite low, it will draw down the battery over time.
Using the 12v power wire for the CVU will only energize the voltmeter when the ignition switch is ‘on’.
When I removed the ammeter, I left the red and yellow caped at both ends. (maybe use for somethng in the future)
Be careful with the black-green wire as that color is used for both the 12v source to the CVU, and the output from the CVU to gauges. 
The power source for the black-green wire is form the rear of the ignition switch.
I would leave the alternator power source connection to the battery terminal on the solenoid.  And use that point to provide power to the fuse block (as done by the factory).