It's probably a Saginaw. How many bolts are there holding the side cover onto the case? Saginaw 3 speeds have 7 bolts, and Muncie SM 318's have 4 bolts. By 1970, I'm pretty sure all the 3 speeds were Saginaw.
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!