Sorry for double posting this but I placed it in the drivetrain forum and got no responce. I have a muncie with the code P9M20 but no model designation. According to CRG this would mean an August 20 build date. I assume that the date was 8-20-68 since there is no model designation which would be there on a 8-20-69 build. Is this 8-20-68 date not to early for a 69 model year car? Also the shaft has one groove so am I correct in assuming that it is a M21? Thanks.

P9M20
P=Muncie
9=Model year of car
M=August of 1968
20th day of month

There is no suffix code stamping of A, B, or C after the day of the month to tell which transmission it was because this was not done until after Oct. 21, 1969. Obviously, your transmission was built prior to this stamping addition. Single groove in the splined area should be an M-21.

The M-21 was used in other cars besides the Camaro. It could be in a Corvette, or teamed with other high HP models like the Chevelle or Chevy II.

[This message has been edited by Silver69 (edited 11-17-99).]

Is your trans still in the car ? Many times the car Vin. # is stamped on the top of the trans. Have you looked there ?