Final Assessment
I've completed the install of the new alternator from Bob at AvantiParts.biz. I believe it's a Remy 55-amp. It fit fine. I couldn't get the battery to charge by hooking up the alternator's BAT to the voltage regulator. I was perplexed because the car was running so much better at idle. It must have just been running off the fully charged battery that I was topping off nightly. But if the new alternator wasn't giving the battery 14.xx volts, then was the original alternator bad? Or was/is the voltage regulator bad?
I ended up taking 14' of 8awg from the alternator's BAT to the battery side of the starter solenoid instead of going to the voltage regulator, with an inline 60amp fuse. However, the regulator is working enough so that the dashboard amp-meter still works (it moves back and forth when the blinker is on), as does the key-on 12v supply to the alternator.
Thanks for all the help with this, my first major project on this fun to drive car.
As always, any comments/suggestions/ideas are still welcomed.