1972 4-speed

[D S.]

Is there an identifying tag or some characteristic on the exterior of the 4-speed transmissions that one can immediately tell if it is an M21 or M22?

Thanks,
Scott Sims
Texas Chapter

[Jim T.]

Re: 1972 4-speed

The sound a M22 makes is a difference and in a stamping of the P with date info the last letter would be a C.

[John H.]

Re: 1972 4-speed

Is there an identifying tag or some characteristic on the exterior of the 4-speed transmissions that one can immediately tell if it is an M21 or M22?

Thanks,
Scott Sims
Texas Chapter

Scott -

The Muncie "P"-stamp on the passenger side at the rear vertical rib on the main case ends with an "A" for an M20, and a "B" for an M21, or a "C" for an M22.

[Bill C.]

Re: 1972 4-speed

scott,

just a guess here , but I would think more than 75% of the 72 454 4spd cars where all M20.
Now this is just from running across a good deal of original ones that I had the chance to look at over the last many years.
The M21 seemed to be used with 3.55 or higher gear ratios, and not with the 3.36 or 3.08 ratios.

This is just an observation - no hard facts to back up the assertion ...

Bill