81 Camaro 4 speed swap

Discussion in 'Transmission & Driveline Topics' started by 04silvyhotrod, May 14, 2014.

  1. Ghostof76

    Ghostof76 Veteran Member

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    327, s like to wind out quick. The trans with it's 2.20 first gear and 3.73 rear your planning may not be enough . Your start line ratio will only be 8.20. 2.20 X 3.73 = 8.20 . You'll be better off with 4.10's despite sucking on the highway. 2.20 X 4.10 = 9.02 start ratio. Much better for that motor.
     
  2. black_aerocoupe

    black_aerocoupe Veteran Member

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    No. Get a 5 or 6 speed.
     
  3. Camaro-Chevelle

    Camaro-Chevelle Veteran Member Lifetime Gold Member

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    When installing steep gears, it is always best to install an overdrive transmission. This will give you the best of everything. You will have great off the line power without sacrificing a comfortable RPM on the highway. A good compromise for now would be to purchase the M21 from your friend. Sell it and find a M20 that will work with your 3.08 rear differential. Save your money and invest it into a Tremec and a rebuild of the rear differential with 4.10s. I know it sounds like a lot of money, but it will be worth it in the long run.
     
  4. 04silvyhotrod

    04silvyhotrod Veteran Member

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    I was thinking about selling the m21 and buying a M20. But the borg warner st-10 has a lower first gear than the m20. I also know where one of them is at. I drive the car right now with the auto but I never did like a auto in a car. The th-350 needs freshened up and would rather put the money on a 4 speed swap.
     
  5. DoTheDew

    DoTheDew Veteran Member

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    I run a ST-10 with a 2.73 gear, turns just nice going down the highway. Has stood up to its fair share of nitrous hits as well, no issues.
     
  6. Jonzz28

    Jonzz28 Member

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    My M21 + LT1 + 3.73 = FUN. I can smoke them off the line with ease, it never bogs, never chatters, and can cruise without it being insane. Now I have an upgraded Ram clutch, so that helps, but it has not left me wanting 4.10's. Not yet anyway. ;)
     
  7. 04silvyhotrod

    04silvyhotrod Veteran Member

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    I've been talking to the man with the st-10 and will be getting it instead of the m21. That way I can run the 3.08 gears out the back.
     
  8. Hey G

    Hey G Veteran Member

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    At Jonzz28, what kind of RPMs do your run @ 65-70 mph on the highway? I have the same combo going in my car...someday.

    G
     
  9. Jonzz28

    Jonzz28 Member

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    At @ 3200 -3400 at 65-70mph.
     
  10. DoTheDew

    DoTheDew Veteran Member

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    Most (not all) of the st-10's came with a low ratio first gear for low speed rear end's like the 3.08, they were designed to work together. Technically the weakest of the bunch due to that low first gear, but I've left hard many a time producing in excess of 300 hp on the juice, and never had an issue.

    Having the low first makes it great in traffic, and the spread between the gears is about perfect.
     

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