transmission numbers

[Ted K.]

Have 68 vette with what I believe to be incorrect 4 speed. I can't find my numbers in any books that I have to tell me what I have.
Help.....
Case number 3851325
Side cover 3831707
Tail piece 3846429
Stamped number on top of case K194855
Thanks,

[Wayne M.]

Re: transmission numbers

Case number 3851325
Side cover 3831707
Tail piece 3846429
Stamped number on top of case K194855

Probably out of '64 Chevelle, assembled at Kansas City around May or June.

[Ted K.]

Re: transmission numbers

Is it still considered a Muncie?
If it is, is it a M-20 M-21 or other

[Wayne M.]

Re: transmission numbers

Is it still considered a Muncie?
If it is, is it a M-20 M-21 or other

Ted -- yes; aluminum case 4-speed passenger car transmissions manufactured at the Chevrolet plant at Muncie Indiana, from roughly 1963 thru 1975, were known to us as Muncies.

If your trans is currently installed in your '68 Corvette, the only way to tell if it is close ratio or wide ratio (they were both called M20 until 1966 model year), is to check your speedo reading at (say) 2000 rpm in 1st gear and 4th gear. If speed in 4th is 2.2 times that in 1st, then its a close ratio (known as M21 from '66-up); if it's 2.5 times [roughly], then it's a wide ratio (2.56 from '63-5; 2.52 for '66-up). With a '429' tail housing, your speedo cable will attach on the driver side, which is not the factory connection side. If your trans is on the bench, just shift into 1st and count the turns on the input shaft versus the output.

There's one other remote possiblility, but only if your '325' was a late '65 assembly; that is, the M-22, of which only a few dozen were made.

Here's a pic of the smokestack of the Muncie plant, taken a few years ago. The plant was partly dismantled then, so this landmark is probably no more.

[William C.]

Re: transmission numbers

Based on the casting # on the case it is a '64-65 version Not as robust as the '68 edition (small countergear shaft and weak synchronizer system)