Hi
I am actually doing the research for my husband, so please excuse incorrect terms.
We have a 69 Z28, confirmed motor & body vin.
Transmission numbers
casting 3925661
spline sleeve/nose 3915020 GM 37
Tail 3857584
Tag 946798
Side cover 3950306
also a backwards 12 hashmarks the first four have four dots in upper level, fifth has 3 dots, last area none
Also saw what I think is two 1/2 0's - looks like cc1 then 40333
I researched most of the numbers, is it really horrible if the case is from 1970? This is a 12/68 -- 1969.
Thanks for helping
the wife of hvac

Mark or Mrs. Mark,

This link to the CRG may be of help to you.

http://www.camaros.org/drivetrain.shtml#TransmissionNumbers

This Chart from CRG should help... along with this photo from CRG.

http://i263.photobucket.com/albums/ii152/tjs69_photos/Transmission%20ID/muncie1.jpg

http://i263.photobucket.com/albums/ii152/tjs69_photos/Transmission%20ID/trans_muncie_code.jpg

Sorry if I steered you wrong, before. - Tom

CC1= counter case 1971, 40333 is the serial number

Side cover 3950306 is 1969
Your other casting part number pieces would fit your year Camaro as long as the casting dates (numbers w/dots in the circle) are prior to the vehicle build date.

Double check your Tag 946798. It should be 3946798 for an M-21 1969 IMPALA, CHEVELLE, CAMARO Z28 L78

I have some dated/stamped and undated/unstamped cases for restoration purposes. PM me if you are interested.

cc1 is an over the counter main case put into the parts system in 1971... Some where in the life of this trans the case was replaced with a main case that was bought in a box at a GM dealer parts department...
Or replaced under warrantee... 40333 is a serial number
cc9(1969) thru cc4(1974) main cases won't have a P# because they weren't assembled at Muncie...

The tag #3946798 is for a 1969 M-21(a lot of times the 3 is flatted by the bolt head)...
3950306 is a 1969 only side cover...
3857584 tail is 1965 thru 1970 model years...
3915020 front bearing retainer is 1967 thru 1974 model years...

Late 1969 calender year build Camaros could have used 3925661 main cases...
(both 660 and 661 main cases were used sept. thru Dec. 1969)

A Dec. 1968 built 1969 Camaro would use a 660 main case...

Hope this helps... Crash