Borg-Warner T-10. Most likely a passenger car transmission used in various car applications- - - -mostly in Fords. Some Corvettes used T10-s in the late 1950s before Muncie started making their aluminum case models. Is the case cast iron, and does it have a Ford or GM bellhousing bolt pattern? Got any pictures? I believe the T-10 was developed from a modification of the T-85 heavy duty 3 speed box used in some Pontiac applications. Can you post any pictures?
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!