Muncie 4 Speed
The term "rock crusher" refers to the noise made by the meshing of the strong-er helical gears in the M22. Later model 1971-''74 Muncies are also popular with racers, because these transmissions used a 32-spline output that is stronger than the early 27-spline, and the newer units seem to perform better in high-rpm and high-horsepower applications.