There were three models of the 3 speed in 2-4. Floor shift, column shift and column shift h.d.
69-70 had two more designations, /6 and V8
I own a 71 bh /6, 3 speed. The car anyway. I have yet to pick up a correct 3 speed and haven't acquired the white ball yet either.
I also own a 70 383 3 speed manual M46 car. Now that I think of it, there is a transmission in that car. I'll have to take a look and see.