Trans Input Shaft ID

[Hotrodpaul]

I am trying to identify P/N 3831766 GP 4.351 and would like to know what the input shaft fits. Any help would be appreciated.

Thanks, Paul

[Mr70]

Paul..that's a Main drive clutch gear input shaft.
Yours is the first design and has 24 teeth.
It was used on the 1965-67 Big Passenger series cars & 1967 Corvettes w/M-21 4 speed Muncie w/2:56-1 1st gear.
It was soon superseded by part #3924781.

[Hotrodpaul]

Rick, thanks for the info. I thought the M-21 used a 2.20:1 First Gear? Unfortunately, the number listed was in an Ebay auction and has already ended.

Thanks, Paul