Interesting T-10 4 Speed Can You Help ID?

[SuperNovaSS]

I bought a storage locker that was auctioned off due to non payment of rent. It had a bunch of Harley parts, a couple Big Block Chevy engines, C3 Corvette parts, and this transmission. All the other parts were fairly straight forward in regards to identification. The transmission seems to be a bit more of an odd ball.

The maincase and tail have late 1972 casting dates and I believe the stamping shows it was assembled the 282nd day of 1972. It has the smaller 7/8 pin and one groove on the input shaft. Anyone know what this is? When I first saw it, I thought it was an early Super T-10 Powerbrute trans. Now seeing the 7/8 pin, I think it may be a simple replacement for an early trans. Can anyone offer any insight?


Thanks,

Jason