Muncie M20
The Wide-Ratio Street Classic
Smooth performance, ideal for street builds and cruising.
- 1st Gear: 2.52:1
- Input: 10 or 26 spline
- Output: 27 or 32 spline
- Known for: Larger 29-tooth countergear, 2 grooves on later inputs
Since 1945, Muncie has delivered the muscle behind America’s most iconic transmissions. Today, the AutoGear Supercase continues that legacy—engineered for modern power with vintage soul.
Learn MoreSmooth performance, ideal for street builds and cruising.
Straight-cut gears, legendary strength. Born for big-blocks.
Smoother shifts, modern materials, and better RPM drop.
Getting you the right gearbox
Our EZ Spec configuration form will help submit your inquiry for one of our gearsets.
EZ Spec FormModel | 1st Gear | Input Spline | Countershaft Teeth | Known For |
---|---|---|---|---|
M20 | 2.52 | 10 or 26 | 29 or 25 | Street-friendly, wide-ratio |
M21 | 2.20 | 10 or 26 | 27 | Close-ratio, racing edge |
M22 | 2.20 | 26 | 27 (straight-cut) | Rock Crusher strength |
M23 | Variable | 26 | Various | Modern refinement + Supercase |