[gtome]

I was just curious if anyone might know. And until tonight I didnt know there was a long and short shaft T-400, so I dont know what it is yet. Anyway, I pulled a T-400 out of a 70 GTO and am putting a m-21 in it. Is there any chance the driveshaft would work in it still? Also I pulled a t-350 out of a 65 Tempest to put the T-400 from The 70 GTO in it. If the 70 GTO auto driveshaft wont work with the M-21, would it work in the 65 with the same t-400? I assume they arent the same wheelbase, so its unlikely, but I thought I would ask.

[android 211]

Thats two different wheelbases and four different driveshaft lengths. Different driveshaft yokes too. Turbo 400 driveshaft length is longer than Turbo 350 and Muncie driveshaft. Muncie and Turbo 350 driveshaft and yoke are usually the same - within '68-'72 years. '64-'67s are longer. I recall driveshaft length was listed in my '69 service service manual per application. You need to look it up and take everything you have to a driveshaft fabricator. 4x4 specialty shops do a lot of that. They can cut the ends off the shafts you don't need and make you one the length that fits right.

['ol Pinion head]

Driveshaft lengths
'68-72 Pontiac A body 2 door w Pontiac V8

w small output shaft Muncie 4spd............56.00"
w super turbine 300 2spd or T350...........56.00"
w shortail T400.....................................55.375"
w big output Muncie or 2nd design t10.....55.375"

-Note all dimensions are center to center on ujoints, and assume original engine mount placement and original style rearend.
-subtract 7/8" from driveshaft length for use of 8.5 A body rear
-Yoke used on T400's & big output Muncies is '67-73 medium length yoke.
-There are at least 11 different T400 yokes that were used by GM from 65-88. use of long style T400 yoke will effect driveshaft length.

[gtome]

Thanks for all the info. And to make it even more confusing, the 65 Tempest the T-400 is going in has a Chevy 12 bolt in it too.