68 340 4 speed bell housing 308 large bearing retainer

mcodecuda said
It just came to me. It must be a 68 or 69 A-body big block 4-speed transmission. I’ll have to check the bell housing applications in the morning.

Scrap that idea. The big block A-body cars all used the smaller bearing retainer. This leads me to believe that this was a transmission that was custom made for a big block A-body where they used a 68 & up big block non A-body bell housing.