['ol Pinion head]

Have owned a few A & F-body partscars that still had their original Saginaw 4spds, one of the last was a '73 LeMans GT which originally was 350 2bbl car. Most of my keeper Pontiacs & projects are big output Muncie 4 speed cars, & I have a rack of Muncies. The Saginaw 4sod transmission uses a coarse spline input shaft & the small output shaft & as such shares same spline driveshaft yoke w '63-70 Muncie 4spd, Super300 2speed autos, & T-350's. Early B/W T-10's & very HD T-10's (PowerBrutes aka Super T10's) sold through speedshops also had 10 spline input shafts & the small output shaft.

For the '71 GM models, the 4spd Muncie transmission received the big output shaft that accepts the T-400 yoke. These late M20-M21-M22 transmissions all originally had fine spline input shafts, though some found today as cores may have a later installed coarse spline input shaft. Overall, the length of the '71-74 1/2 Muncie 4soeeds was decreased slightly over its preseessor, & when combined with original medium length T-400 style driveshaft yoke, the driveshaft that was used is the same as same year & model year Pontiac A or F-body with a factory installed "short tail" T-400.

Second Design B/W T-10's, these were introduced during the late '74 model year, mainly seen in performance F-body's & A-body's, but also installed in Vettes. This 2nd design T-10 also has fine spline input shaft, big output shaft, & shares same overall dimensions as the '71-74 1/2 Muncie 4speed. To use in a vehicle that previously had an early Muncie 4 spd, or Saginaw 4 speed, will need a 5/8" shorter driveshaft with the correct medium length T-400 yoke.

2nd design T-10's picked up the nickname Super T-10 though they are NOT the original Speedshop sold high nickel gear PowerBrute T-10's/where the nickname was originally derived! Ratio wise, the most common 2nd design T-10's are the 2.64 1st gear (wide ratio used small block Chevy/Camaro). Next there are 2.43 first gear (close ratio... 455 & W72 400, as well as used in L82 Vette's). There is also the 3.42 1st gear (ultra wide ratio) version used in '81 305 F-body's, & with a funky tail housing w a panhard bar mtg provision, '82 T/A's & Z-28's. Less i forget, there is a seldom seen version that was used in '79 301 4bbl T/A's.

Swapping from a Saginaw 4 spd to either mfg of big output shaft 4speed trans, will need the correct length driveshaft, correct shifter linkage, & correct shifter mounting plate for either of the big output shaft 4spd transmission. Then, can mount just about any factory equipped GM Hurst style shifter. The Inland (ITM) 4 speed shifters can also be made to work with the correct Muncie or 2nd design T-10 shifter linkage. Reverse back drive linkage is different between Saginaws & Muncie 4 speeds & these correct pieces are often hard to come up with . Speedo cables, also often have to be changed due to different cable routing when used w different transmissions in same bodystyle, have not gone through a Saginaw swap out in a while so somewhat foggy on this.

Tthe easiest swap from a Saginaw 4spd equipped car w a nice condition used 10.4" clutch disc, pressure plate, & flywheel, would be going to an early Muncie 4spd out of an A-body, F-body, Nova, Vette, or Chevy big car. Will need correct era Muncie 4 spd linkage. I would avoid the early Muncie 4spd's which ran the 7/8" counter pins. Most common of these have the "325" case. These are the weakest of the Muncie 4spds, & as cores often have a stretched pin hole in the case. With propper machine work the "325" cases can have their countershaft pin holes machined (w a slight taper) to accept the later 1" counter pins, then they can be rebuilt with the later style gears, making them somewhat stronger, have gone down that road before.

Best to what ever you decide to go with.

Happy 4th of July!