Originally Posted by 31ROC
So, doing a search for M20...and most ads are saying their M20 should fit 67-70's Chevrolet.....if I have a mid to late 70's 350, will this tranny fit?
Also.....will the M20 have the correct spline counts input and output?
The tranny mates to the bellhousing and yes, the same bellhousing that fits the earlier blocks will fit your block. Put another way, any M20 will work, but it takes a bellhousing to connect the tranny and engine together.
The M20 can come from any GM vehicle, mine is from a Pontiac for example. So don't pass one up just because it doesn't say it's for a Chevy.
The input splines will determine the clutch you use, so there's no problem there. Older trannys (1962-'70) used the 10 spline input, newer trannys (1970-'74) used a 26 spline input. But you can get a clutch for either spline that will work for you. It's the output shaft spline count that can mean a different drive shaft yoke is needed or not.
The earlier M20 output shaft has 27 splines- the same spline as the tranny you have now. Or it can have a 32 spline output, this was used on the newer trannys.
You will need to install a pilot bushing
in the crankshaft, this is what locates and supports the end of the input shaft.