I have a Muncie that I am trying to identify. The main case is a 3851325, the tailhosing is a 3846429 and the side cover is a 3831707. These numbers narrowed it down to a 1964-1965. The input shaft has one ring. Using that and the dates above I believe it is M21. Will still open the case and check the gears just to be sure.

I tried to locate a vin or serial number on the case to narrow down its application but can't find them. The only number I found is 4111172 stamped in the flange. What is this number? All of the documentation I found statesthat the vin and serial numbers start with a letter.

Any ideas?

Casting: 3851325 Years: 1964 - 1965 Ratios: M20 2.56 1st , M21 2.20 1st

Year 1963-1974 Type: M21 Rings: One Ratio: 2.20 / 1.64 / 1.28 / 1.00 / 2.27

Looks like a M21

I have the same tranny tailshaft number (63-65), but I opened my case anyway yesterday = M21

It's a 64 M-20 close ratio------------------THAT'S RIGHT, AN M-20.
In 63-65-----------------------THERE WERE NO M-21s OR M-22s.
ALLLLLLLLLLLLLLLLLLLLLLLLLLLLL 63-65 Muncies were M-20s. They were all M-20s, and either the close or wide ratio version.
The seperate distinction of M-20, M-21, M-22 did not occur until 1966.
The 325 main case was used 64-65.
The 429 tail housing was used 63-64--------------------------EXCEPT on some Pontiacs such as the GTO, which used the 429 tail housing up to about 70.
The SINGLE groove around the input splines identifies it as a close ratio Muncie.
Yes, yes, yes, I know, it appears that some EARLY 65 cars got a Muncie with the 429 tail housing. But for the most part, the 65 Muncies got the 584 tail housing.
Thus, you most likely have a 64 close ratio Muncie. If you can locate the VIN stamped somewhere on the maincase, it will identify the make and year model of car that it came out of.

All I could find on the case was the 4111172. Where are these numbers normally located?

I tried to locate a vin or serial number on the case to narrow down its application but can't find them. The only number I found is 4111172 stamped in the flange. What is this number? All of the documentation I found statesthat the vin and serial numbers start with a letter.

Any ideas?

My opinion is that 4111172 is the CON VIN for a 1964 Corvette. The Corvette plant at St. Louis didn't use S in the CON VINs for the early Corvettes. 4 is the model year followed by the six digit sequence which falls right into the 100001 to 122229 range in 1964.

1963 Muncie's used a 731 tail housing, not 429...
In 1964 the St. louis plant built full size Chevys and Corvettes...
Full size cars used the S in their VIN... Corvettes used the last number of the model year (4) in their VIN... Hope this helps... Crash

Just remember boys that this transmission is over 40 years old. Who knows what's inside, without taking it apart and checking?

I was planning to hang this in a 69 Camaro we are putting together. Is it worth more to a vette owner or are they a dime a dozen? I have another one with the same casting numbers but this one has P1121 and 824B8938 stamped in it.

1963 Muncie's used a 731 tail housing, not 429...


Yes, 63 Muncies did get 731 tail housings, but there were also two versions of the 429 tail housing used in 63, a "thin" and a "thick" rib version.