My 67 442 originaly came with a muncie 4 speed but now has an automatic. How do I tell which one ,M21 or M20, did it have? I determined by rotating the rear wheels that the rear ratio is around 3:20. I'm heading off the a large swap meet tomorrow and want to keep an eye out for one.
Thanks,
Ragtop

 

I have three Munice transmissions and am looking to sell two of them (I am likely keeping #2 below). I will eventually be posting these on Racing Junk as they have been modified for circle track racing. They are no longer four speed transmissions and will need to be fixed before you could use them in your street car - unless you want to drive around in a two speed. These are worth more as racing transmissions but wanted to give some Olds guys a first crack at them. I am not looking to get rich on these but also am not interested in tire kickers. I understand its not cheap to ship and also it will take some work to put these in a street car. I will work with anyone seriously interested via PM. If you or anyone else is serious i will sell them for a fair price and be happy to coordinate shipping or pickup if local in the Springfield, Hartford,Worcestor area. Stands are heavy and would be included if you want.

Shifters / linkages not included. None of the ears are cracked and I will do a close inspection prior to shipment. I havent spent too much time on these since i brought them home from the race garage. I will take any additional pictures needed to help you know what these are. So if a specific pic is needed let me know.
Numbers as follows:
#1
Main Housing Casting #3885010
Main Housing Stamp P7C23 (March 23,1967)
Tail Housing Casting #3857584
Side Cover Casting #3950306
Stamping on top of main housing is 7U132990
#2 (likely the one i keep)
Main Housing Casting #3925661
Main Housing Stamp P0702B
Tail Housing Casting #3857584
Side Cover Casting #3884685
Stamping on top of main housing is T536555
#3
Main Housing Casting #3925660
Main Housing Stamp P9M???
Tail Housing Casting #3857584
Side Cover Casting #3950306
Stamping on top of main housing is N508195 (or 6)

 

The standard for a 3.23 gear set was a three speed manual or optional Auto, no other factory or dealer options.

The 3.55 had the M-20 standard but M-21 and M-22 were optional as well as the Auto. A build sheet obviously would answer your question completetly.

 

"no other factory or dealer options"? Don't know what you mean by that, but the 3.23 was an optional gear set for the 4-speed.
M-20 and M-21 were optional, but the M-22 was *not* available in '67!

Ragtop, with the original trans gone, there is no way (without paperwork) to tell whether it was an M-20 or M-21. Even the POP won't help you there.

 

I will be leaning towards the M20. From the prices I've seen at the swap meet this past Sunday in Ct, I will just buy one already rebuilt. First I will need to find all the other parts such as peddels, linkage, shifter and the other hard to find stuff. I still have a lot of research to do.
Thanks for the replies. I will keep you in mind "boldsmobile" as I do live near Worcester.
Gary