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Lock-up v. Non Lock-up Transmissions

Discussion in 'The Garage' started by skink4president, Dec 10, 2005.

  1. skink4president

    skink4president Registered Member

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    Apologize if this has been discussed before:o I read something recently about lock-up transmissions and rear end gearing. For a while I've been considering a 350 turbo to 700R4 swap ( I do a lot of highway driving). What's the rule of thumb regarding gearing and non-lockup/lockup trannys or overdrive/non-overdrive? (Right now I'm running a Turbo 350 w/ 3.08 gears front and back in my '73 k5.)

    Thanks!
     
  2. beastofablaze

    beastofablaze 1/2 ton status

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    Not really any rule of thumb...but since you have OD you can afford to gear big and not pay a big price in mpg.

    One rule of thumb when regearing is match the gears to your tire size... more important than anything else.

    What size tires are you running?
     
  3. 1977k5

    1977k5 3/4 ton status Vendor

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    Hopefully 31's with 3.08's!:eek1:
     
  4. skink4president

    skink4president Registered Member

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    Yeah, I'm running 31's. The 3.08s are stock. I thought most all 73's were at least 3.55s or more but I've counted, they're 3.08s. I plan on adding about 2-3" of lift and eventually going with 32 or 33" tires. What's the equation to determine ideal gearing for specific tire sizes. Isn't there a calculator out there for this?

    Thanks.
     
  5. 89GMCSuburban

    89GMCSuburban 1/2 ton status

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    If you are doing a 700R4 with 33's, I'd run 4.10 gears. I had 33's and 4.10's for the move up here and it worked great....13 MPG great.
     

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