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gearing

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 90blzr, Mar 27, 2001.

  1. 90blzr

    90blzr 1/2 ton status

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    Just want some help on deciding what gears to run with 38 or 39.5 tires. Some say 4.56 some4.88 and 5.13. I drive by blazer alot and have a 350TBI with 700R4 trans. Any opinions?
     
  2. Burt4x4

    Burt4x4 3/4 ton status

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    Pic the middle 4.88!! Any one of the three will work! The taller the gear the hire your RPM on the Hwy will be so........sup to you

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    <A target="_blank" HREF=http://www.burt4x4.coloradok5.com>http://www.burt4x4.coloradok5.com</A>
     
  3. 6.2Blazer

    6.2Blazer 1/2 ton status

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    Since you have the 700r4 with overdrive, I would recommend at least 4.88 gears. I believe Steve (aka Colorado K5) is running 4.88's with 37" tires.
    Just remember that once the tranny shifts into the .70:1 overdrive, if would effectively make 4.88 gears the same as 3.42 gears when it comes to engine rpm, so I don't think you would have to worry about too high of revs on the highway.
     
  4. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Someone recently posted this.
    <A target="_blank" HREF=http://www.4lo.com/geartable.html>http://www.4lo.com/geartable.html</A>

    Bad Dog

    85 K30 CUCV, 350 TBI, TH400, NP205, D60/C14, 4.56
    Coming soon: 4" lift, 40" tires, massive cutting, shorter wb and rear overhang.
     
  5. CaptCrunch

    CaptCrunch 1/2 ton status

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    I'd go either 4.88 or 5.13's w/ the overdrive... 4.56 if you do a lot of street and want decent milage at highway speeds... but ideally 4.88's would be good now and still ok if you bust the 700r4 and decide to move to the stronger th400 setup.

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  6. KrebsATM02

    KrebsATM02 1/2 ton status

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    I hope you still don't have stock axles

    Doug Krebs
     

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