I just purchased a muncie trans and I would like to find out what it is. The #'s are 3925660 the date code is P8K9L the other #'s are 189481676. Thank you for any help you might be able to provide.

there should be some stamped on numbers on the verticle flange in the center. Pxxx (letter A/B/C)

A=m20
B=m21
C=m22

Originally posted by sunk99:
I just purchased a muncie trans and I would like to find out what it is. The #'s are 3925660 the date code is P8K9L the other #'s are 189481676. Thank you for any help you might be able to provide. 3925660 is 68-70 Muncie 1" Bore Patent Number
P8K9L is P=Muncie, 8=1968, K=July, 9L should be a number between 1 and 31 for a date; I'd check it again. Muncies didn't get the A, B, or C designator until 1969.

Are there any rings on the input shaft? An original shaft M20 will have two rings, a M21 will have one ring, and the M22 will have no rings. Again, assuming it's the original input shaft.

The last number makes no sense at all except it looks like the code to match the trans to the original car. If that's what it was (189481676) it'd be 1=Chevrolet, 8=1968, 9 should be a letter for the assembly plant, 481676 should start with 1xxxxx for the last 6 digits of VIN. Since it can't be the VIN code, can't imagine what it is. Is this stamped or cast? :confused: