He's probably going to swap the back end frame for one with the brushes in a different location. There's a definite geometry difference between the ones that turn CCW from the drive end and the armature windings that affect where the brushes need to contact the commutator bars. Thank goodness for old geezers!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!