Jughead

I have an M-20 now but have read that the input shafts may be different? :confused: 26 spline, 10 spline? :confused: Why the difference? I guess I can't tell which I need with the tranny in the car? :D

Gordonm

The 26 spline shaft came in 71. The 71 and later transmissions all had 26 splines and the larger 32 output shaft. I have and M20 with a 26 input and 32 output. The early M21 had the 10 spline input as did early M20 trans.

Flareside

Len, why the M21 over the M20? The M21 is considered stronger, but the 2.20 first gear ratio isn't exactly "optimal" ;)

redvetracr

You might consider a Super T-10, Richmond has two boxes with the best of both worlds a lower 1st gear (than a M-21) for take off and a second and third that are close ratio about the same as the M-21
...redvetracr

Jughead

That's the reason....I was told all BB came with the M-21 standard and the M-20 couldn't handle the torque.

redvetracer---you have mail.

70PurpleLS7

Len,

Whoever told ya that all bigblocks came with a M21 is mistaken. My 70 came from the factory with a LS5 and was equipped with a M20.

Keith

Jughead

Thanks Gordon. So, if I have an early M-20 with the 10 spline, what would I need to use the 26/32 shaft tranny's? :confused: The proper 26 spline clutch & new 32 pline yoke?

Muncie challanged & deficient! :D


[Modified by 1970 Stingray, 6:29 PM 1/19/2003]

Gordonm

Just get the proper 26 spline clutch disc and a 32 spline output yoke and you should be good to go.

Jughead

:cool: :cool: :cheers:

Marks69BB

I have the OEM M20 also (came stock on BB AC cars). As far as I know, there is no diff between the M20 and M21 as far as strength goes (the M22 is another matter), just the ratios of the lower gears is different. I think the M20 is better because it has larger gear ratios in 1st and 2nd which is better for low end pull for the strip or street.

chuck d

Mark69BB is right. If you have 3:90,4:11,4:56 gears the close ratio (M-21) is great. On the street with high gears, 3:08,3:36, 3:55 the wide ratio (M-20) works best. There is no strength differance between a M-20 and M-21.

Chuck D