Question About Non-Synchro-First-Gear Manual Transmissions

With further research the transmission I'm describing (in post 34) seems to be a "Chevy/ GM/ Muncie 318 3-speed" rather than a Saginaw, which was just a guess. Apparently the barrel in the middle is referred to as a synchro clutch assembly and I believe it is a fairly unique design. It may not be the best one to get your teeth into if your learning about synchronisers.

But it's described somewhat in this video.