Well. New alt arrived and looked like it had already been installed by somebody. greasy hand prints, grease on the mounting foot.
Either way, i installed it. Got it in and all tightened up. seems to be slightly more misaligned than the last one, but i can tweak that.
Tested good, 14.5v at the alternator during idle, 14.4 at the battery.
I again tested for a poor ground by checking between the alternator body and the negative battery terminal. It showed -0.03 volts, so there is a voltage differential of .03 which is way smaller than they say to watch out for.
I revved it up to 1500 rpm and had high beams, AC fan, heater fan all on high and checked, it was -0.05v at the negative terminal, and -0.08v between the body or the radiator, etc. So, again, still under .1v.
We'll see how long it lasts....