I MEANT Chrysler, as in Plymouth! No Delco about it. The "IGN" terminal was the sense connection, a blue "IGN" wire went to one field terminal and the green wire from the regulator went to the other field brush terminal. Before that they had a similar alternator and a one-relay mechanical regulator. And alternators that had bearings that wore out. AND it took a special tool to remove that pulley and change the front bearing.

 

Toyota is a bit strange (cheap?) grounding the battery with the cable going to the chassis, near the fender.
I'm not sure what ends up conducting the high currents (starting, charging) then to the... engine block where the party is.
Old cars ground the battery to the engine block, with a smaller ground wire to the body. A few car makers uses braided ground straps from the motor to the chassis. But all this costs money for copper lol.
Reading a low charging system voltage, I would measure the alternator's actual output (output bolt and the block) to make sure there is no bad connection, as wll as the voltage difference from the block and battery(-).

There is no problems with the charging system. All works according to specification.
The whole impetus to this thread is whether my old Lead Acid batteries were past their useful prime and whether the voltage read after resting over night was a fairly good indicator of the battery needing to be replaced. THAT question has been answered. Yet some keep going back to whether the charging system is working properly. It is.
The batteries have been replaced, Wet cell for AGM types. Only AFTER making the change did I discover that AGM's take a higher charge voltage to properly maintain them. Fortunately for my wife's car I have a modification solution to be performed next week when I get materials needed. I have another thread on that subject so I won't be going into that detail here.
Nevertheless, thank you for your contribution.