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Projects 4 speed munci ston crusher tranny

Discussion in 'The Hokey Ass Message Board' started by jc555247, Jan 2, 2009.

  1. jc555247
    Joined: Jan 1, 2009
    Posts: 29

    jc555247
    Member

    I am about ready to start ( once again) working on an old project, my 1955 Chevy 210. It has a 1969 350 truck engine with what we used to call a 3/4 race cam and it HAD a 4 speed Hurst hooked to a 4 speed munci tranny. However some years back some one helped them selves to the tranny and the shifter. I am now looking for a 4 speed munci or a suggestion for a replacement. (PLEASE DO NOT SUGGEST AN AUTOMATIC) That would be worse then 3.2 beer and a new wedding ring :mad:
     
  2. I know that the T5 5-speeds are popular and somewhat more available then a Muncie 4-speed. I'd bite the bullet and get another M21 and either get a rebuilt one or go through it yourself, spring for a new quality shifter and be done with it forever.

    Bob
     
  3. I would stick with the muncie and hurst both are easy to find. Be sure to get the later muncie with the 1 inch cluster shaft. If you want new try the Richmond in either 4 or 5 speed.
     
  4. jc555247
    Joined: Jan 1, 2009
    Posts: 29

    jc555247
    Member

    where do I start looking for the M21 munci?
     

  5. The M20 was the smaller cluster gear shaft, 3/4" I think. The M22 was the "rock-crusher", so named because of the straighter cut on the gears and the resultant noise they made, although most would call it music!
     
  6. zman
    Joined: Apr 2, 2001
    Posts: 16,633

    zman
    Member
    from Garner, NC

    You seem to be allergic to e's... Muncie? Stone? Even though it's rock crusher... :D:D:D
     
    Last edited: Jan 2, 2009
  7. Any decent transmission shop should have a barrel of munci's in the back.
     
  8. 54BOMB
    Joined: Oct 23, 2004
    Posts: 2,107

    54BOMB
    Member


    Oh , stone crusher I get it :), Ive been looking at this thread all day trying to figure out what the hell he was trying to say.
     
  9. geage
    Joined: Jan 25, 2008
    Posts: 94

    geage
    Member

    hurst shifter for a munciE on ebay buy it now 215.00, NO WONDER YOUR WALKED AWAY
     
  10. jc555247
    Joined: Jan 1, 2009
    Posts: 29

    jc555247
    Member

    I think it walked away one night when I was knocking on doors for "YOU BETCHA"
     
  11. ma70tt
    Joined: Nov 14, 2008
    Posts: 135

    ma70tt
    Member

    the borg warner t-10's were the same thing too. available up to '81 in the z28 camaro. shouldnt be too hard to find one of them.
     
  12. scrape
    Joined: Sep 22, 2003
    Posts: 1,131

    scrape
    Member

    try craigs list for a muncie.......
     
  13. racer67x
    Joined: Oct 30, 2007
    Posts: 261

    racer67x
    Member

    pretty hard to beat a Munchie stone smasher..
     
  14. A cheaper alternative to the Muncie or any other 4 speed is a Muncie 3 speed from a 1/2 ton pickup. You can find them for $75-$150 and they're quite strong.
     
  15. Toymaker
    Joined: Mar 26, 2006
    Posts: 3,924

    Toymaker
    Member
    from Fresno,CA

    I found my Borg Warner Super T-10 on ebay for $400. It came out of a Camaro, had the 2:88 first gear ratio I wanted and was in good shape. You can still buy the tranny new from Richmond I think, and the Super T-10 offers better 1st gear ratios IMO for Drag Racing if thats your thing.
     
  16. Jason455
    Joined: Jun 21, 2004
    Posts: 515

    Jason455
    Member

    The lower the first gear, the less torque the tranny will take before it explodes. M-21 (2.20 first) is a close ratio, m-20 is a wide ratio (2:52 first) rock crusher had gears cut straighter. I believe rocks were all 2.20:1 from GM. There a tons of aftermarket parts for these.
     
    Last edited: Jan 4, 2009
  17. The Shocker
    Joined: Dec 30, 2004
    Posts: 3,538

    The Shocker
    Member

    I thought it was the other way around.M20's had 2.56 low and M21's and M22's had 2.20 low.I could be wrong and most of the time i am ,but i thought the M20 was a small block trans and the lower first gear was to make up for the lack of low end torque versus a Big Block ...
     
  18. A super T-10 or a muncie. I saw a recent post with a M-21 for $575.........I think. There's a guy around town here that gets over a $1000 out a rebuilds M-20 and 21s, $1400 for a M-22.
     
  19. twofosho
    Joined: Nov 10, 2005
    Posts: 1,153

    twofosho
    Member

    ALL Muncie 4 speeds were upgraded to the larger countergear shaft about mid 1968, but unless you plan on high RPM clutch drops with sticky tires it's probably a moot point. About the same time they started using bolts to mount the shift arms to the side case instead of studs and nuts. Not a foolproof ID, but fairly reliable when an original transmission is in a car.

    Of greater importance on a transmission with high mileage or abuse is the fact that the countergear shaft bore is unbushed and the countergear shaft causes the aluminum case to egg out over time misaligning the counter gear.

    Wide ratio (M20) Muncies are usually listed as having a 2.52 or 2.56 low gear and need to be used with a 3.31, 3.42, or 3.55 rear gear (as usually supplied by the factory) for optimum street operation.

    Close ratio (M21 or M22) Muncies have a 2.20 low gear originally designed to be used in road racing Corvettes. As a result they could commonly found with 3.31, 3.55, 3.73, 4.11, or 4.56 rear end ratios, although most street cars would carry 3.73 and 4.11 ratios. Drag racers found out early on that using a VERY steep rear end gear ratio (at least 4.11, but not unusual with 4.56, 4.88, or 5.13 if the engine would rev high enough at the finish line) with the transmission ratios closer together resulted in lower elapsed times.

    If you need or want more detailed info, a good place to start is the HAMB search button, as there have been many Muncie threads posted.
     
  20. marylandmuscle
    Joined: Nov 28, 2007
    Posts: 65

    marylandmuscle
    Member

    I have put togther a bunch of Muncies. I currently have about 14 cores which I build on request-

    The M20 is a wide ratio box, the M21 a close ratio box. The M22 does indeed have straighter cut gears hence the term rock crusher.

    '65 and pre 65 cases have a 7/8 inch counter shaft, post 65 a 1 inch counter shaft. Casting numbers ending in "325" are the 7/8 shaft, cases ending in "010", "660" "661" are the 1 inch counter shafts- the casting numbers translate as follows:

    010- 1966-67
    660-1968-69
    661 - 1970-73

    There are 10 spline course input shafts through about 1970 and then fine spline inputs after. The last 1970-73 cases have two drain plugs though I am told there are two plugs on the early cases used for the M22s.

    BTW all the gears are the same except for the input shaft and cluster gear-these are matched to designation of M20, 21 or 22 and these give you your overall gearing.

    This is from memory but should be generally accurate.

    For a 1969 case with new bearings, gaskets, syncros, washers, hand cleaned case, new hardware etc- I typically would ask for about $950. I do them locally on request.

    Chevy by the Numbers will translate casting numbers, and the web sources will give you an idea as to gearing ratios.
     
  21. I have a variety of them here and they're great transmissions. I have one with a great 1st gear that works nicely in heavy cars.

    Bob
     
  22. Smokin' Joe
    Joined: Jul 4, 2006
    Posts: 1,000

    Smokin' Joe
    Member Emeritus

    jc555247, I just sent you a PM
     
  23. more Muncie info:

    Year 1963-1965 Type: M20 Ratio: 2.56 / 1.91 / 1.48 / 1.00
    Year 1966-1974 Type: M20 Ratio: 2.52 / 1.88 / 1.46 / 1.00
    Year 1963-1974 Type: M21 Ratio: 2.20 / 1.64 / 1.28 / 1.00
    Year 1967-1974 Type: M22 Ratio: 2.20 / 1.64 / 1.28 / 1.00

    [​IMG]
    M20-M21 have a 30* gear angle

    [​IMG]
    M-22 has a 20* gear angle

    input shaft tooth & spline count by years
    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

    serial & vin numbers
    serial numbers begin with the letter "P" for Muncie plant

    serial numbers 1963 to 1966 included only the month and day.
    P0101 would indicate January 1st.

    1967 to 1968 the number got a year designation & a letter designation
    for the month such as P8A01, meaning January 1st 1968.

    1969 to 1974 Muncies got a ratio designation at the end of the serial number.
    An example would be P4D23B. This equates to April 23, 1974, M21 ratio.

    month code
    January Letter: A
    February Letter: B
    March Letter: C
    April Letter: D
    May Letter: E
    June Letter: H
    July Letter: K
    August Letter: M
    September Letter: P
    October Letter: R
    November Letter: S
    December Letter: T

    ratio codes for 1969-1974
    Letter: A M20 Ratio
    Letter: B M21 Ratio
    Letter: C M22 Ratio

    case casting numbers, related to production years & ratios
    Cast:3831704 Year:1963 Only Ratio:M20 2.56 1st ,M21 2.20 1st
    Cast:3851325 Year:1964-1965 Ratio:M20 2.56 1st ,M21 2.20 1st
    Cast:3885010 Year:1965-1967 Ratio:M20 2.52 1st ,M21&M22 2.20 1st
    Cast:3925660 Year:1968-1970 Ratio:M20 2.52 1st ,M21&M22 2.20 1st
    Cast:3925661 Year:1970-1974 Ratio:M20 2.52 1st ,M21&M22 2.20 1st
     
  24. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    Put a Toploader Ford 4-speed behind it. They make a bellhousing for it.
     
  25. the shadow
    Joined: Mar 5, 2005
    Posts: 1,105

    the shadow
    Member

    A buddy of mine is trying to sell a m-22 rock crusher (dated '71) he just had it freshened up. Pm me if you interested and i'll pass on his contact number.

    Paul
     

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