Help Id'ing an old Muncie Case & Tailshaft..

[dutch]

If anyone can shed some light on what I have shelved here and planning to get rid of - it would be much appreciated.
Aluminum Maincase - Casting Number 3851325 date code stamped P 0 18 (date code casting circle markings below the casting number are a 4 in upper half of the component casting circle with 3 dots in lower half) and it has what appears to be 7/8" mainshaft diameter bore hole..
Aluminum Tailshaft Housing - Casting Number 3846429 (speedometer hook up on the driver's side)
There is no VIN stamped on Maincase and boss for drain plug isn't drilled or threaded..
I know these are Muncie 4 speed bits - but other than that I'm limited and thinking earlier than 67 or 68 year and casting date marker makes it from the 4th month and 3rd week of whatever year it was produced in - as well as being a May 18th installation of whatever year also - and no drain hole means no M22.
The lack of VIN probably means prior to GM worrying about POP or warranty tracking like the late 67's or 68 versions and onward.
I'm thinking M20 or M21 but other than that is there anything else to add?
I'm hopeful of finding some more info before advertising it for sale - so I can be helpful of definitively and accurately assisting someone who may be looking for such bits for a specific year or model application.
Additionally could anyone add their impressions of what both of these might be worth - they are in excellent condition (no Sidecover unfortunately) and there are no cracks or wear marks in the ears or anywhere inside or out!
Thanks for any assistance!  Randy 

[bertfam]

The 3851325 main case was used in 1964 and 1965. The 3846429 tail housing was used in 1964 to February of 1965. Looks like you have some very old stuff there.

Ed

[dutch]

Ed - worth anything to anyone considering the age - or possible application possibilities in your estimation?

[TangoBravo]

January 8 is the build date. Would be Jan 8, 1964 if the case has "PAT.PEND." cast on it.  " US PATENT NO 3088336" would be a January 8, 1965 build. The 1965 case would also have a squared off upper extension housing boss. Not too many people are excited over 7/8" countershaft cases. Probably good for someone needing the specific model year Muncie. 
ADD: Grooves on the input shaft should help with M20 or M21

[bcmiller]

It’s worth something to someone.

The 429 tail housing has a drivers side speedo outlet. Used by Pontiacs into the late 60s.

[dutch]

January 8 is the build date. Would be Jan 8, 1964 if the case has "PAT.PEND." cast on it.  " US PATENT NO 3088336" would be a January 8, 1965 build. The 1965 case would also have a squared off upper extension housing boss. Not too many people are excited over 7/8" countershaft cases. Probably good for someone needing the specific model year Muncie. 
ADD: Grooves on the input shaft should help with M20 or M21

It does have US Patent 3088336 cast on it - and I'm not sure where I got the May idea from - as I see your date code logic - just not sure what the '0' or 'O' means but I guess it is pretty old for sure..
No internals just empty case and tailshaft..
We're the 7/8" shaft versions all that poor - I can see why they might get upgraded, but I'm sure they were put in many very heavy vehicles around that timeframe..?
I t also has a couple of square bosses molded into the case next to the upper part of the rear flange so that may be what you refer to as the 'square bosses'..  THANKS!

[bcmiller]

Send me a pic of the P 0 18 area

[TangoBravo]

It does have US Patent 3088336 cast on it - and I'm not sure where I got the May idea from - as I see your date code logic - just not sure what the '0' or 'O' means but I guess it is pretty old for sure..
No internals just empty case and tailshaft..
We're the 7/8" shaft versions all that poor - I can see why they might get upgraded, but I'm sure they were put in many very heavy vehicles around that timeframe..?
I t also has a couple of square bosses molded into the case next to the upper part of the rear flange so that may be what you refer to as the 'square bosses'..  THANKS!   
Answers: The date codes were done as Factory "P", Month "01", and day "8"  for 63-66 transmissions. The coding was changed in 1967 model years to have a year designator added between the factory and month positions. Yours should be a 1965 model year  built on January 8, 1965. Yours is a M20 or M21 (M22 transmissions were first built in March/April 1965 using 3851325 cases that had the casting numbers milled off. The countershaft holes were increased to the larger 1" size.) The upper boss on the back of your case should be squared off, not rounded as earlier cases were made. Countershafts were increased to 1" in 1966 model year.

[dutch]

Thanks for all of the help with this today.
Not quite sure how to try and proceed with this as I'm not sure where its value if any resides or where to best try and advertise it.. but I'll give it a few days and look at some sites where the general MO is larger bodies cars like the Chevelle  or possibly GTO and Pontiac sites and see if there is a For Sale section that might give me some ideas or pricing of similar stuff to go by.
Much appreciated is the info certainly!
Randy

[Kelley W King]

If you take it to a swap meet probably $50 to $100 . If the case has all 4 ears and never been repaired the 4 speed guys would want it. If it were a case with a vin on it , it might be different.

[dutch]

Yea - that is what I was thinking in that it could without a vin stamp on it, be considered a 'Born With' unit for anyone who has a need for a date coded M21 or M20 tranny for an appropriately dated car - but up here in Canada that is pretty much an extremely long shot to say the least..
The case is perfect and the ears have no cracks and the main shaft hole appears to have no wear on it since I've read where they often can get sloppy - so for anyone who can dredge up the proper internals it could be a perfect deal - but again I doubt there is much interest up here, but we'll see..
Again - Thanks to all who chimed in to assist me in figuring out what it was originally!