Thanks for the great info. I was able to id the trans as a 1970 M-20 with the two grove input shaft and 2.52 first gear ratio, which will be perfect behind the 283 in my 57 Chevy.

Bad news: Broken teeth on input and cluster gears.
Good news: Got it for $50.

Now I'm finding out that the input is $313 and cluster $360! Bearing kit $225.

So, now I am looking for parts. Help!!