th350 to M21 swap - first impressions

Discussion in 'Transmission & Driveline Topics' started by willem, Mar 9, 2019.

  1. budro6968

    budro6968 Veteran Member

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    Is it the same with the engine off? Can you shift easy while not running foot off the clutch? Does it act different while the engine is running? If running can you ease the clutch out while trying to put it in 1st and feel it pull in to 1st. I think it is probably an adjustment thing. You shouldn't have to break in the shifter. It should be smooth from the get go.
     
  2. DesmoEd

    DesmoEd Veteran Member

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    Swapping in a 4 speed on my RS totally transformed the car.

    Are you sure you are running an M-21? If so you must have at least 3;73 out back as the close ratio Muncie had a 2:20 1st gear that can be a little lazy off the line, especially in a 3500lb car.

    I went with the wide ratio 2.52 1st gear M-20 - with a 3;73 axle out back its good but the 1-1 final drive got old really quick. Car has been down for a while and a TKO600 is in the works.

    I agree with the other comments about breaking in the shifter. I don't have any experience with Summit's shifter, I used the Hurst Comp plus and its probably the best option. It has a very strong gate that must be breached on the left before you can access reverse. I used all the GM pedal and console stuff and the install came out fairly nice

    [​IMG]
     
  3. C4Racer

    C4Racer Veteran Member

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    Hey congrats Willem. Nicely done.
    I have the motor back in my car with the T56. Going through all the details. Clutch seems to work !! So that’s good. Can’t wait to drive it. Not because of the OD but because of the control. Almost all my performance cars have been manual. It’s jusy how I’m wired !
     
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  4. willem

    willem Veteran Member

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    u put a magnum in there? ill get the car back saturday with the new shifter. will update
     
  5. C4Racer

    C4Racer Veteran Member

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    yes sir. Close ratio version. New from Bowler.

    [​IMG]
     
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  6. willem

    willem Veteran Member

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    Damn that looks killer!
    So I got my car back and it's - a dream come true.
    If it keeps behaving like this I don't think I'd ever want a TKO.
    I'd have to switch from 3.73 to 3.08 and UP the power though, which is never a bad thing anyways.

    The front seal on the trans gave out after a couple rides and starting gushing oil inbetween bell and engine sump, so the trans was taken off and that seal was replaced.
    However today after getting home i have a new small leak over there.. reading through the net it seems muncie's are REALLY prone to leaking...
    unless someone has some excellent insights on how to avoid this particular leak 'ill leave it as is for the moment...

    Apparently I can hook the vacuum line to the manifold through a "filter box" that would absorb any accidental oil gushes from the trans (to avoid it from entering into manifold) . have to read about that but it could improve avoiding oil leaks during driving so it's claimed..

    thanks for everyone tuning in and a SPECIAL THANK YOU to DAVE who put in the time to school me (during the install as well) and provide me with an excellent alternative to that garbage SR shifter :D
     
  7. dave@ztech

    dave@ztech Veteran Member Lifetime Gold Member

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    Sucks about the leak, are they sure they have the right gear oil in the , what Muncie specified for it? And if yes, did they use synthetic ?
     
  8. willem

    willem Veteran Member

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    there's currently 80/90mineral in it.. should i switch?
     
  9. dave@ztech

    dave@ztech Veteran Member Lifetime Gold Member

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    The 75-90 fluid should be fine , and if if not syn, then it shouldn't be the cause for the leak, maybe over filled?
     
  10. willem

    willem Veteran Member

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    im reading up on it.it looks common. maybe also case related. illput up a new thread when ive delved into it as much as i can
     
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