Resistance in hot circuit...small gauge 12V type cables
Dirt or corroded cable end connections
bad contacts in starter switch another souce of resistance
bad ground...easily caused by either newly painted parts or old. rusty and filthy stuff
I would first try direct cable jump from battery to starter terminal, then add in a second cable from starter bolt (cleaned up and bare) to battery...
then you can worry about starter itself.
It would be good to say...which engine if stock, if not entirely stock what components are we talking about??
There are 3 different '32 starter circuits in '32...