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Author Topic:   transmissions gear ratios
22 racing
Member
posted June 08, 2003 09:52 PM
could someone tell me where i can find the gear ratios for a muncie 4spd thanks


jhon hollomon
Member
posted June 08, 2003 10:00 PM
Have you tried the tool box in the main menu on the upper left of this screen? It says m-21s and m-22s are 2,20 1st, 1.64 2nd, 1.28 3rd, and 1.00 4th and m-20's are 2.52 1st, 1.88 2nd, 1.46 3rd , and 1.00 4th.

[This message has been edited by jhon hollomon (edited June 09, 2003).]

crew42tx
Member
posted June 08, 2003 11:20 PM
I dont think that they have the ratios for the muncies in there if you will count the lines that go around the input shaft I can then let you know what they are.


c21
Member
posted June 09, 2003 11:04 AM
Copied and pasted from: http://peachstatechevelles.com/muncieid.html

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Muncie 4-speed indetification
Case casting numbers, relating production years and ratios available

Casting: 3831704 Years: 1963 Only Ratios: M20 2.56 1st , M21 2.20 1st

Casting: 3851325 Years: 1964 - 1965 Ratios: M20 2.56 1st , M21 2.20 1st

Casting: 3885010 Years: 1965 - 1967 Ratios: M20 2.52 1st , M21 2.20 1st, M22 2.20 1st

Casting: 3925660 Years: 1968 - 1970 Ratios: M20 2.52 1st , M21 2.20 1st, M22 2.20 1st

Casting: 3925661 Years: 1970 - 1974 Ratios: M20 2.52 1st , M21 2.20 1st, M22 2.20 1st

Ratios of the M20 , M21 , M22

Year 1963-1965 Type: M20 Rings: None Ratio: 2.56 / 1.91 / 1.48 / 1.00 / 3.16

Year 1966-1974 Type: M20 Rings: Two Ratio: 2.52 / 1.88 / 1.46 / 1.00 / 3.11

Year 1963-1974 Type: M21 Rings: One Ratio: 2.20 / 1.64 / 1.28 / 1.00 / 2.27

Year 1967-1974 Type: M22 Rings: None Ratio: 2.20 / 1.64 / 1.28 / 1.00 / 2.27

Input Shaft Tooth and Spline Count Related to Year

Year 1963-1965 Type: M20 Rings: None Spline: 10 Tooth Count: 24

Year 1966-1970 Type: M20 Rings: Two Spline: 10 Tooth Count: 21

Year 1970-1974 Type: M20 Rings: Two Spline: 26 Tooth Count: 21

Year 1963-1970 Type: M21 Rings: One Spline: 10 Tooth Count: 26

Year 1970-1974 Type: M21 Rings: One Spline: 26 Tooth Count: 26

Year 1967-1970 Type: M22 Rings: None Spline: 10 Tooth Count: 26

Year 1969-1974 Type: M22 Rings: None Spline: 26 Tooth Count: 26

Please note that there are 7 different Muncie input shafts. All 26 spline inputs came with 32 spline output shafts and all 10 spline inputs came with 27 spline output shafts. A common mistake is thinking that all "fine spline" 26 spline input shafts are M22 heavy duty types. This is not true. An M22 gearbox has a 20 degree helix angle on the gearset as opposed to a 45 degree angle. Also M22 gear sets were of a higher nickel alloy. The straighter angle was designed to produce less end loading of the gear train and less heat but created more noise, thus the nickname "rockcrusher". The higher nickel alloy allowed for more impact of the gears. Another misconception is if you have a drain plug you have an M22. Again this was only true when the first M22 boxes were created. But all 3925661 castings had drain plugs.

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I'm running 2nd in an M-20 from (if I remember correctly, the casting #s will tell you) 1967 (1.88 2nd ratio) with 3.23 in the back. Just over 6.07 final. Turning about 5800 on a semi-banked 3/8ths.

When the "loose nut behind the wheel" gets more consistent, might could see 100-200 more RPM. We were hoping for the 6000 RPM ballpark and it is (so far) working well.

Hope that helps.

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