Used, not working, March Performance billet aluminum performance alternator.
It was charging only to about 10-11 volts.
Removed from a 1969 Mercury Cougar, but should be applicable to similar year Mustangs.
Engine was a 351W. Believe alternator was 140 amps, model P2651-05.
Although alternator is not working, the billet aluminum case is in excellent condition.
Have all the internal parts, so if you're familiar with restoration and automotive electronics, there should be some good usable parts here and possible rebuild.
It was replaced with a March Performance MCH-P2563-05 alternator from Summit Racing.