I haven't been happy with the charging system in the 260Z for a while. At startup, the alternator output was fine, but after a while of driving, the voltage would drop down to only 12.8VDC many times. It was time to explore options. Since I converted the carburetors into throttle bodies for the Patton Machine GM TBI fuel injection, I wasn't using the neutral (yellow) wire from the alternator for the fuel pump relay #1. That meant I didn't have the limitation a stock 260Z owner would have. (Of course, I could have worked around that one if needed.)
Because I like experimenting on my projects, I decided to look into the Nissan Frontier 70A alternator. Since I didn't feel like paying ZCarDepot $150 for their setup, I searched RockAuto and found a new SKP for $86.79 (minus 5% discount and plus tax and shipping) alternator for a 1999-2004 Frontier 4 cylinder. On Amazon, I found the pigtail for the alternator $10.99 + tax.
I took out the old voltage regulator (still a points style - Sorry, @Dave WM, I didn't try to adjust it first. It looked bad on the bottom to me.) and found the bottom side full of helicopter seeds and somewhat corroded. I tried some different bullet lugs to see if I could connect wires to the engine harness to run to the pigtail. That was a no-go. However, I found some alternatives. The white/red wire to the alternator positive had a smaller white/red wire with a female bullet to connect to a condenser on the old alternator. I would prefer to have a different sense wire, but it would work. Then I noticed that the condenser at the VR was connected to the black/white wire. There was my switched source. I would just need to make a small jumper harness to connect the pigtail and condenser to the black/white wire.
For the most part it was a matter of removing the old alternator and installing the new one. I did have to replace the lug on the white/red wire because the positive post on the new alternator was much larger. That was no big deal, though it took some time to enlarge the hole on a 1/4" lug to make it fit on the M7 (or M8?) post.
I shot some video that I need to edit that may help others with the swap. I'll see how it turned out and post a link.
Here the Frontier alternator with the 260Z externally regulated alternator.
Here's how the wiring looked when I was done with the installation.
Here's the pigtail on the alternator going to the positive post for sensing voltage.