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331 Ext Hemi W/ M21 Muncie Clutch Questions

Discussion in 'The Hokey Ass Message Board' started by ksxr94, Jan 20, 2014.

  1. ksxr94
    Joined: Mar 21, 2013
    Posts: 3

    from NJ

    Hey folks, I have my first real technical question for you guys out there….here goes:

    I am building a 31 Dodge Sedan, putting in a 331 extended, industrial block hemi that came off of a generator in a factory and putting behind it an M21 Muncie. I already got the adapter plate from Hot Heads, but the question I have relates to the guts since I have no real experience with installing manual transmissions.

    <O:p</O:pI have seen other posts regarding these blocks, but nothing that specifically says what parts to use for a manual trans.

    <O:p</O:pWilcap gave me a couple particulars and said to call McLeod racing for parts and they gave me different particulars…I just want to know what will work well, and what others have done…no theories.

    1. <O:p</O:pFlywheel - Can I use the original flywheel from the engine? It is 146 tooth, never been machined.<O:p</O:p
    2. Clutch/PP - What size clutch/pressure plate - Wilcap says 10-1/2”, McLeod says 11”:
      1. Clutch Disc
      2. Pressure Plate – Wilcap indicated using a Borg/Beck style, while McLeod recommended a diaphragm style that they make<O:p</O:p
    3. Hydraulic throw-out bearing – Wilcap indicated using a #1400-20, while McLeod recommended a #1300….McLeod says that the 1400-20 should only be used when the bell to fingers is greater than 3” (not sure of the measurement til I get the clutch/PP.<O:p</O:p
    I know both places are leaders in the industry but just want to make sure I get the right stuff from the start.

  2. 73RR
    Joined: Jan 29, 2007
    Posts: 6,325


    You must use the correct oem 146 t flywheel as it needs to engage the oem starter.
    The clutch diameter is your choice; the flywheel can be redrilled for whatever pressure plate style/diameter you use.
    I suggest that you buy a hyd t/o bearing package for an oem application that uses the trans you have, then use the pp for that application so that all of the critical parts are packaged for that use.
    The trans and clutch parts do not know, or care, if they are bolted to a 331 Hemi flywheel or if they are bolted to a 68 Buick 430 GS...

  3. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,839


    If you have a diaphragm make sure you get the right style release bearing. Some require a rounded face others a flat face bearing.
    Last edited: Jan 23, 2014
  4. fatkoop
    Joined: Nov 17, 2009
    Posts: 712


    Made that mistake years ago on my 331 hemi /'47 Ford. Destroyed both the pressure plate and the bearing in about 1000 miles.
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  5. ksxr94
    Joined: Mar 21, 2013
    Posts: 3

    from NJ

    Thanks guys, I'm assuming McLeod should be able to match the pressure plate to the correct hyd t/o bearing. Trying to determine which t/o bearing to use now. I'm told the flywheel is already drilled for an 11" clutch and that the diaphragm style is nicer for my use, so I'm going to go this route. Just need to determine if the 1400 t/o is too tall and the 1300 will work better.

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