Originally Posted by PanzerSD

It was a Dixie rebuilt thru a local parts shop here. It's replacing the AL117X 70A alternator.
This rebuilt is actually putting out 80A at 2000RPM, so it's a pretty well rebuilt alternator.
I've determined that the general lack of charging at low RPM in these older cars is lack of a properly sized drive pulley. I made the driven pulley smaller by placing a washer between the two discs, and gained 2.5 volts. Now I've been successful in achieving an adequate charging voltage at 600RPM. My additional problem still exists however, high loads at low RPM drains the battery. This may require relocating pulley drive to a smaller pulley or upgrading to a newer alternator beyond the typical AL129X upgrade.