I am taking stock and have two drivelines that I labeled 30 years ago as from a 57 I had in the late 60's. Trans shafts have 21 splines assuming I measured right in the dark. I thought one was the drive line I ran behind a T-10 (27 spline output) but I must be wrong. Do stock 57 3 speeds have 21 spine output?? Or has time ravaged my memory???

I am taking stock and have two drivelines that I labeled 30 years ago as from a 57 I had in the late 60's. Trans shafts have 21 splines assuming I measured right in the dark. I thought one was the drive line I ran behind a T-10 (27 spline output) but I must be wrong. Do stock 57 3 speeds have 21 spine output?? Or has time ravaged my memory???
Checked the spline count again its 16 not 21

The last run of the T-10 was 27 spline like the Muncie, 62 and 63 I know was the same. I'm not sure the year they switched from the 16 to the 27 but after late 63 they also switched to the Muncie in the big chevy, 409, and the late production runs of the 63 vette.

Thanks for the reply. I'll just have to get the tranny and see what output shaft it has. The more I think about it I'll probably try and unload it on a Corvette guy that needs a number matching one and get a later model Muncie.

Orrie,
There are 2 sizes, and 3 spline counts on Chev tranny tail shafts. The 3 and 4 sp (B-W, Saginaw, Muncie), PG, TG, Turbo 350 all have the same size tail shaft. The 62-earlier have 16 splines and 63-later have 27 splines-----------------but they're the same size.
The Turbo 400, 71-74 Muncie and 75-later Super T-10s have the bigger tail shaft with 32 splines.

Thanks, thats what I needed to know. Now I just need to compare universal joint sizes and see if I can mix and match to get one that is workable out of the parts stash.