71 up 2.47 to1 and 2.66 to 1
All transmissions that are not 18 spline are 23 spline and are considered small spline. They did make a 30 and a 26 spline main shaft / output shaft for short tail A-F body transmissions. That is not what they are talking about in the diagram above.
Main shafts are all interchangeable with cases and gear sets except OD's they are a different diameter internally. Which gets into more depth then being discussed. The only thing that needs to be changed when going 30 to 26 main shaft is the tail shaft which is only available for A-F body transmissions.
What I do know is you can take an F-body aluminum case and tail shaft and install a 18 large spline /Hemi internals into it using the 30 spline main shaft from an A-body. Yes the front bearing cover bolts right on from the Hemi box. Then if you take the side cover from an overdrive truck trans and install it you will have an all aluminum hemi 4 spd. for an A-body car.
Below are two pictures of Hemi transmissions. One is a standard synchronized trans. The other is a liberty non synchronized trans , Shift without the clutch. Know as the crash box back in the day. They were used in mopar and other brands for racing. The 3rd and 4th pictures show a mopar input and a GM input
Small spline is 23 spline input. Large spline is 18 spline input / Hemi 4 spd.
All transmissions that are not 18 spline are 23 spline and are considered small spline. They did make a 30 and a 26 spline main shaft / output shaft for short tail A-F body transmissions. That is not what they are talking about in the diagram above.
Main shafts are all interchangeable with cases and gear sets except OD's they are a different diameter internally. Which gets into more depth then being discussed. The only thing that needs to be changed when going 30 to 26 main shaft is the tail shaft which is only available for A-F body transmissions.
What I do know is you can take an F-body aluminum case and tail shaft and install a 18 large spline /Hemi internals into it using the 30 spline main shaft from an A-body. Yes the front bearing cover bolts right on from the Hemi box. Then if you take the side cover from an overdrive truck trans and install it you will have an all aluminum hemi 4 spd. for an A-body car.
Below are two pictures of Hemi transmissions. One is a standard synchronized trans. The other is a liberty non synchronized trans , Shift without the clutch. Know as the crash box back in the day. They were used in mopar and other brands for racing. The 3rd and 4th pictures show a mopar input and a GM input