I'd start with a new battery and retest. I suspect the alternator or voltage regulator is bad, too. It may be as simple as overworking the alt. while trying to charge a battery that won't take a charge.

4 hours ago, Zedyone_kenobi said:

I pulled the alternator this morning (wearing my osha white safety socks - those who have followed my Z build will understand) and plan on taking it to get tested this afternoon. None of my connections were lose or corroded. No matter what I do the amperage never changes or moves with revs and the battery will NOT read more than 12.3 volts.

The problem is that I don't see the results of the tests I suggested you do.

On 4/28/2025 at 10:48 AM, SteveJ said:

Since the car is modified, the field wire is jumpered to the ignition wire, and the neutral wire is jumpered to the battery wire.

So this is not the factory setup for a 71? Does it have Dave Irwin's internal regulator modification?

I am currently running the MSA 60 amp alternator kit. It was purchased back in 2010.

All my tests were at the battery. After I get the alternator tested, I will run the tests SteveJ mentioned. If the alternator comes back bad, then issue solved.

2 hours ago, Zed Head said:

So this is not the factory setup for a 71? Does it have Dave Irwin's internal regulator modification?

I have seen the diode fail open in that design before. That would keep the car from charging. Also, if the ignition fuse in the fuse box is blown, it won't charge. The test I asked @Zedyone_kenobi to perform would help to identify those problems.

Worry not my good man, your words of advice will not go unheeded. I will check out those parts this evening when I get home. A simple Alternator test is just one more part of the equation. It is simple and free.

8 hours ago, Zedyone_kenobi said:

I pulled the alternator this morning (wearing my osha white safety socks - those who have followed my Z build will understand) and plan on taking it to get tested this afternoon. None of my connections were lose or corroded. No matter what I do the amperage never changes or moves with revs and the battery will NOT read more than 12.3 volts.

Zedy…..Glad to see you still wearing your steel toed safety socks!!!!

Okay update

All fuses are okay.

One of the female spades in the "T" connector has 12.7 volts with the key off. The key in the Run position reads 11.8V but that also powering a electric fuel pump, so that is fine

The alternator test at the parts store?

The alternator tested a big green check at the parts store.

However, I tried to test to find any out put from the T connector while the alternator was running

well I got nothing, but it would see that it fried my volt meter LOL LOL. I am sure I should have measured the red/white wire from the back of the alternator instead. But now I have to get a fuse for my voltmeter or a brand new voltmeter... which would not be horrible.

Now I have no idea what the test read, as it only comes back with a big green check. No voltage out put was displayed. According to the 72 Z wiring diagram the red/white wire runs back to the fusebox, so that seems like it should be supplying the car with power after the car starts. My problem is that the wiring diagram shows the voltage regulator and I am running an internally regulated alternator. So I have to figure our which wire it is that should be charging my battery and which is supplying the car with power (me thinks red'white)

Where did you take the alternator to be tested? If you don’t have someone at a parts store that’s competent on testing you might want to go to a local Napa store or an establishment that has a machine shop. Counter people look at a screen and most don’t have experience on working on vehicles. My HO. Ok I vented. Wish luck friend.