1964 Muncie M21

[Dave C.]

I have a 1964 Jan 6 build car 365 horsepower with a close ratio muncie. I understand that they were not termed M21 until 1966. What I am trying to figure out is whether I have the right tailshaft or not. It is a 429 but has a flat pad on the bottom versus a narrow rib. Does anyone know when the change was made in 1964?

Thanks

Dave

[Tom P.]

Re: 1964 Muncie M21

Tail SHAFT-------------or tail (extension) HOUSING? There is a difference between a shaft and a housing.
If you mean the tail HOUSING for the transmission, the one with the 3846429 casting number is correct for 64

[Dave C.]

Re: 1964 Muncie M21

Tail shaft extension housing. There were 2 housings that ended with 429 for the 1964 model year. Another source is now claiming the change was made in September of 1963.

Thanks