Round back alternator

HERE IS the story. Mopar alternaters WERE ALL "round back" up through maybe 72ish or so.

Round backs up through 69 had one insulated brush and one grounded brush

Round backs starting in 70 had TWO insulated/ isolated brushes and used the newer "flat" electronic regulator.

All square backs have two insulated/ isolated brushes

YOU CAN USE ANY isolated brush alternator with a 69/ earlier regulator simply be grounding either brush and hook the other to the regulator.

Some round backs as pictured had provisions for BOTH a grounded brush and two isolated brushes. THIS CAN BE BAD as I've seen "rebuilt" ones come through with ALL THREE BRUSHES installed. This can short the blue field power and burn up a harness

Worse, "rebuilders" used to DRILL THE CASE of older grounded brush roundbacks and install an aftermarket isolated brush so they can sell them as 70/ later. THESE ALSO can come with all three brushes installed