Anyone with a couple of brain cells to rub together and some machine tools should be able to adapt a modern bypass stat to the 261 housing. Start with a thick chunk of aluminum and whittle away anything that doesn't look like what you want. The trick will be finding one of those thermostats that opens at less than 195 degrees.
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!