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Ok voltage drop test shows .59. Voltage at the VR red (top) terminal is 14.75 and gren wire 0 with motor off key on . Running the red shows 14.75 and the green keeps cycling from 8-10.5. Amp gauge shows discharge with the lights on but never shows a charge. Volt meter on dash shows 15+ and flickers and the VOM shows 15.8 at the battery. I also noticed when you start the engine the volt meter will sit at battery voltage for a second and then climb to 15+. Just to be clear the power feed doesn't go through the amp gauge like the older trucks. Ignition switch is new and bulkhead connector shows no corrosion. Could a bad diode or something in the alternator be causing this?

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So battery is 15.8v. Red wire at the alt is 14.75. Drop should be ~1.05v, which you're seeing half of that.

Next test: Run a jumper wire directly from the battery + to your red wire at the alternator and start the car. This bypasses that voltage drop, and should immediately bring the battery down to a normal voltage.

Also, if you turn the key off with the jumper in place, it will continue to run until you remove it

To test for a bad diode, put your voltmeter on AC and put the leads on the battery. You should see less than ~100mVAC. If you're seeing multiple volts AC, then a diode is bad.

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Disconnected the red wire at the alt and jumped from the field terminal to the battery and the charge dropped to 14.7 but when I shut the key off the engine stopped as normal. What does that tell us? BTW thanks for all the advice I'm getting from everyone.

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14.7 at the battery Still a little higher than I like, but better than almost 16.

Normally, when the key turns off, it kills the power to the ignition system.

When I did my test, I didn't disconnect the red(blue) wire at the alt - so when I turned the key off, the ignition system continued to have power, and the engine ran on. Your regulator still got power only through the key, so that's why it turned off when you flipped the key.

Now for the fix... you have ~1v of drop from going through the bulkhead (twice), ignition switch plug (twice), and the switch itself. You can either start probing the wires along that path until you find and fix the bad connection(s)... or what I did was install another relay to power the ignition system, triggered by the old blue wire.

I know you say most of that is new, but there's still a bad connection somewhere

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Look for a bad connection somewhere in one of your heavy load lines. Like the one that goes up the steering column, at the bulkhead, etc. I had a burned connection on my column. Drove me and a few garages nuts for about 2 years. One day I noticed a black streak in the heavy wire in the plastic coupler. I bypassed the coupler and that cured the overcharging.

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I had the stock plug on the alt BATT wire that ran along the VC to fire wall. the spade clip was burnt.

it would over charge poping the headlights and dash lights. did this 2x before I found the wire trouble and re-spiled it.

I also had problems with the big thick triangle connection on the fender well. Batt wire to the fusable link wires.

replaced alt 2x along with VR 2x headlights 4x. fixed those 2 connection and has been fine ever since.

I can post pics of those connections if you need a looky see stumpy.

that seem to be the trouble spot on all of the mid 80 trucks i work on.