3.23's and a muncie?

Discussion in 'Got gears?' started by BLT4SPD, Nov 2, 2004.

  1. BLT4SPD

    BLT4SPD Well-Known Member

    I built my car out of parts from a few cars. The rear came out of a worked skylark. It is a 10 bolt posi with 3.23's in it. I converted the car to a 4 speed muncie. Any thoughts on how this will work? Good Idea ....bad idea? :Do No:
  2. 87GN_70GS

    87GN_70GS Well-Known Member

    I've got 3.23's with my 4-speed (2.2:1 first). Kinda slow off the line IMO, not enough first gear multiplication. But if you're not racing, it's just fine.
  3. BLT4SPD

    BLT4SPD Well-Known Member


    Thanks for the reply...I dont race, but I hit the street pretty hard. What combination would you recomend for the best acceleration / driveability combination. I have a friend at richmond gear that owes me a favor. :Brow:
  4. flynbuick

    flynbuick Super Moderator Staff Member

    3.23 is the best all around street/road gear in my opinion. We have had 3.23s in two cars. They allow more acceleration than the tires will permit at anywhere near full pedal.

    Just do not put in too much cam as it may slow you down on practical street driving-- meaning stoplight to stoplight.
  5. 87GN_70GS

    87GN_70GS Well-Known Member

    I would shoot for between 9 and 10:1 overall first gear multiplication. A wide ratio trans (2.56 first) with a 3.55 will get you 9.1:1.
  6. BLT4SPD

    BLT4SPD Well-Known Member

    I dont recall what the first gear ratio is, but its a muncie M-21 ( unfortunatly not a rockcrusher) but the cam I have is TA performance's 500hp street cam. I think the lift is around .499 but im not sure, the engine was built a year ago, and Ive been messing with other parts since then. I had a chevelle in highschool that had 3.73's in it, and I liked the feel it had. Im figuring the trans was the same, the gears are pretty close.
  7. mainebuick

    mainebuick Well-Known Member

    When I put the m-21 in my '66, I was running a 2.93. changed them over to 3.23 and it works fine now. :TU:
  8. buick64203

    buick64203 Just plum crazy Staff Member

    The gear ratio on an M-21 and an M-22 are the same :

    2.20/ 1.64/ 1.28/ 1.00

    The 66-74 M-20s has a slightly steeper first gear:

    2.52 / 1.88 / 1.46 / 1.00

    I believe GM used the M-20 up to 3.42 gears. Anything steeper got the M-21
  9. BLT4SPD

    BLT4SPD Well-Known Member

    I've been told by a few friends that I should get a stronger than stock driveshaft. They tell me that with a ~600 Hp and as much torque as the buicks make, the weakest link in the chain is the driveshaft. I drive very hard, and use centerforce clutches, and when they grab hold, there isnt much flex. Does anyone here agree that a stock driveshaft is insufficient?
  10. BirdDog

    BirdDog Well-Known Member

    It depends on your traction. If you're running a real street tire you'll never have enough traction to really hurt a good stock driveshaft. But if you have "big-nasties" or "street slicks", you may have a problem.

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