Two things I see possibly wrong on your testing is no regulator and no load for the regulator to load that alternator and no amp gauge or volt meter to see the output from it
I've watch many stock Mopar amp gauges work when I accidently flooded a motor at the races and saw the amp gauge almost peg for 2 to 5 minutes charging the battery back up.
I have also disconnected the field lead at the races when testing and tuning to see if the car would slow down or pickup without the alternator charging, it would slow down a small amount in ET and MPH That was with a stock single field 1963 Alternator with new brushes and charging the battery up with a battery charger in the pits before starting it up and getting in line to run