Table of Contents

## How many splines does a Muncie 4 speed have?

On the far right is the M22 26-spline input shaft. In the 1970s, virtually all Muncie four-speeds had 26-spline input shafts….21.

Muncie Four-Speed Gear Ratios | |
---|---|

M20 Wide-Ratio 1963-’65 | |

First Gear | 2.20:1 |

Second Gear | 1.64:1 |

Third Gear | 1.28:1 |

## How much horsepower can a M20 take?

Models

Version | Displacement | Power |
---|---|---|

M20B25 | 2,494 cc (152.2 cu in) | 125 kW (168 hp) at 5,800 rpm |

M20B27 | 2,693 cc (164.3 cu in) | 92 kW (123 hp) at 4,250 rpm |

90 kW (121 hp) at 4,250 rpm | ||

95 kW (127 hp) at 4,250 rpm |

**What are the different types of Muncie input shafts and countershafts?**

From left to right are the three basic Muncie input shaft/countershaft combinations. On the left is the M20 countershaft and 10-spline input shaft. In the middle is the M21 countershaft and input shaft. On the far right is the M22 26-spline input shaft. In the 1970s, virtually all Muncie four-speeds had 26-spline input shafts.

**When did the Muncie M22 have a 10-spline input shaft?**

The standard 10-spline input shaft found its way into new Muncie M20 and M21 transmissions from 1971-’74. 9. Here’s another view of the M22’s input shaft and countershaft.

### What is the ratio of the Muncie M21 transmission?

The 2.20:1 ratio first gear is usually referred to as the Muncie M21 transmission; based on GM’s production codes. The 2.56:1 ratio is referred to as the M20.

### What is the first gear on a Muncie transmission called?

The 2.20:1 ratio first gear is usually referred to as the Muncie M21 transmission; based on GM’s production codes. The 2.56:1 ratio is referred to as the M20. Muncie also had a second close-ratio transmission coded M22 and known as the “rock crusher,” which was used behind performance big-block engines and in some Corvettes.