A simple picture would be easier to ID for us non numbers folks

 

I believe those are case casting numbers. There should be other numbers stamped vertically near the main case parting line.

 

Aluminum case, 7 bolts in the side cover and reverse lever in the tail housing = Muncie.

 

Yes those are Muncie casting numbers. “010” is 66-67 main case and “429” is 66-70 Speedo cable on drivers side tail shaft. Saw that on “chevellestuff” recently

 

Thanks for the help everyone. I’ll take a closer look at it tonight and see if I can get more information off of it.

 

Hi everyone, I have a transmission I’m trying to identify. I think it’s a Muncie? Here are the numbers I was able to pull off of it. Thanks in advance for any help.
GM Patent # 3088336
3885010
3846429

The 3885010 main case, as already mentioned, is a 66-67 ONLY Muncie main case.
The 3846429 tail housing -----------DEPENDING ON THE CAR-------------- could be 63-64 or EARLY-65 for a Chevrolet or Corvette (Chevrolet went to pass side speedo fitting in mid-65). BUUUUUUUUUUUT, some cars such as a Pontiac GTO used that tail housing up through 1970. Therefore, IF IT IS AN ORIGINAL, UNTOUCHED Muncie, then I would be willing to speculate it came out of a 66-67 Pontiac (a stamped date code will have the year), maybe a Lemans or GTO.
If you can locate a STAMPED VIN, and if it begins with a 1, then it came from a Chevy product. If it begins with a 2, it came from a Pontiac, 3 is Olds and 4 is Buick.

Here is a comparison of Muncie tail housing with the hole for the speedo fitting on the passenger side (left housing) and the driver side.

 

7 different versions

Guide to Muncie M20, M21, and M22 Four-Speed Transmissions

A close look at the Chevrolet Muncie M20, M21, and M22 four-speed transmissions.

www.superchevy.com

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I had a 65 Chevelle Supersport in High School Graduated 75. This will give you an idea of the what you could buy then. Bought it from a neighbor for 120.00 with Bellhousing, Clutch and throwout bearing. Bought a Hurst Shifter for 30.00. Dropped a 396 with ported heads, 360hp Vette cam. I think it was a M21. Bracket Raced it with slicks and not a hiccup. Great Tranny! Just pound it shifting what I just don't feel you can do today?

 

Just pound it shifting what I just don't feel you can do today?

WHY NOT! ?

 

Everything you ever wanted to know about casting numbers & cases!

Muncie 4 Speed Transmissions

Muncie 4 Speed Transmissions and Parts

 

Ok, I was able to get some more info on the transmission. I apologize, I forgot to say that it is in a 68 Chevelle, but it’s not the original tranny for that car. Here’s what I’ve got to add. The code on the passenger side rear of the tranny is P7B16. I believe that is Muncie Plant, 1967, Feb 16. There are 7 bolts on the drivers side casing. Also the input shaft has 10 splines with two notches in it.

 

Some pictures I was able to get

 

1967 Muncie. There are other indicators to tell if it’s an m20 or m21. Such as one groove on input shaft = M21 and two grooves on input shaft is M20.

 

You are correct on the date code. For sure, it is a 67 wide ratio Muncie (M20).