Doesn't the 1941 cooling system have a non-pressurized radiator? If so, running a 180 degree stat might be pushing the envelope a little toward a boil-over before the thermostat opens. I'd recommend installing another 160 and see if the one you took out was bad. Also, a zero pressure radiator needs to have a considerable amount of expansion room in the top tank- - - -keep the coolant just above the level of the radiator core to keep coolant from being puked out of the overflow.
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!