[79 Phoenix]

Originally Posted by unruhjonny

The 69-74 Muncie three speed only had two ratios:
The ‘car’ or “B” ratio: 2.42/1.58/1.00
The ‘truck’ or “A” ratio: 3.03/1.75/1.00
I believe that GM’s designation for this transmission was an SM-330 - but depending on the model year, platform or model, it could have one of several RPO’s.
I have read on occasion that some full sized cars could get the “A” ratio, but to date I have not found anything to confirm this.

My observations suggest that “B” gear set transmissions always had a front bearing retainer with an OD suited for a car bell housing, and a tail shaft for a floor shifter, while “A” gear set transmissions always had a front bearing retainer with an OD suited for a truck bell housing, and a tail shaft with no provisions for a floor shifter.

Saginaw three speeds seem to be another case all together;
I gave up on trying to understand GM’s coding for them, and what gear sets they came with;
in part because I didn’t have a baseline to compare anything against…

Good to know. Thanks!