[Ronj1969]

Just curious if this is a direct swap ? Will the drive shaft yoke and actual drive shaft be the same ? Will the shifter rods be the same ? I know reverse is different. Will the shifter mount up correctly ?

I’m trying to decide between the Muncie and the Birg Warner super T-10

[tom s]

Go ST-10 or Muncie.

[Jack Gifford]

Oops! Fat fingers...

[PontiacHO]

Seen more older BW Super T-10 transmissions with distorted cases than Muncie transmissions. The Muncie transmission cases can be bushed when worn. There’s many different spline count input shafts on both. What’s the first gear ratio on either transmission and your final drive ratio?
A 3.42 BW isn’t ideal with a 3.55 rear and lower gear. It makes for the need for a really early shift like a “granny gear”.

[Elarson]

Originally Posted by Ronj1969

Just curious if this is a direct swap ? Will the drive shaft yoke and actual drive shaft be the same ? Will the shifter rods be the same ? I know reverse is different. Will the shifter mount up correctly ?

I’m trying to decide between the Muncie and the Birg Warner super T-10

Your '77 originally came with a Super T-10 with 2.43 first gear.
Here's a good reference from Richmond gear....who continues to make the Super T-10 and parts.
The published "torque rating" is pretty conservative. I drag raced a '77 with 455-HO and 9" slicks and didn't break the ST-10.

https://www.richmondgear.com/wp-cont..._MANUAL_v2.pdf

Eric

['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!

[John Milner]

My 74 GTO came with a Saginaw from the factory. I ended up going with a 32 spline T400 style output Super T10. I used a 1976 Trans Am Hurst shifter and linkage. I had to adjust the linkage as the shifter mounting bracket I used was different than the factory Trans Am style bracket which placed the shifter further back around an inch. I used Hurst shifter bracket #7773 and that placed the shifter right in the middle of the factory shifter tunnel and center console. As Roger said, you'll have to get the correct clutch disc, yoke, and shifter linkage if you go with the large T400 style output transmission. Your 1-2 and 3-4 Saginaw linkage might work but I don't know for sure. There is a speedometer cable extension that will work to lengthen your speedometer cable so it will attach to the speedometer drive on the passenger's side of a ST10 transmission. It also may be needed for a Muncie if you get one with the speedometer drive on the passenger's side. Also agree that a 64-70 Muncie would probably be the easiest swap. However, either can be made to work with the right parts.

[Ronj1969]

I think I’m going to go with a 66-67 Muncie m20 as I believe the pressure plate,Clutch disk,output yoke and Drive shaft should all be the same ? Does this sound true ?

[mgarblik]

Originally Posted by Ronj1969

I think I’m going to go with a 66-67 Muncie m20 as I believe the pressure plate,Clutch disk,output yoke and Drive shaft should all be the same ? Does this sound true ?

66-70 M20 would be a direct bolt in. 10 spline input, larger 1" countershaft diameter, small, 27 spline output, same overall length as a Saginaw. 64-65 M20 would be a direct bolt in as well, but smaller, weaker 7/8" countershaft and some other modest internal changes to the synchronizer assemblies. It would work if you happen to find one. 66-70 is a better gear box.

[Ronj1969]

Just picked up my freshly rebuilt Muncie m-20 I believe it’s a 1967 model as it has the larger 1 inch in in the front. I did not get the correct shifter rods I was told my Saginaw rods would fit. I’m curious as to if my hurst shifter will bolt up directly to this bracket on the Muncie or not trying to get this all sorted out so the install will go flawless. Any and all help is appreciated

[John Milner]

That looks like a 1970 Firebird/Camaro shifter mounting bracket. That will bolt to the tail housing of your Muncie fine and a Hurst shifter will fit it fine. You may be able to use the 1-2 and 3-4 rods. You will need another reverse rod as the Saginaw uses a longer reverse rod.

Usually, no grooves on the input shaft of a 10 spline Muncie mean a 1965 M20 or an M22 if 1966-70. I have had at least 1 Muncie that had an aftermarket input shaft with no grooves and was a 1" pin M20.