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3.08 vs 3.36 Chevy rear end

Discussion in 'The Hokey Ass Message Board' started by usmile4, Dec 16, 2013.

  1. usmile4
    Joined: Jul 28, 2005
    Posts: 689


    In my 51 Chevy, I have a 56 Chevy rear end behind my 235 with a 5 speed. Right now I have a 3.55 gear but was wondering about changing to a 3.08 or a 3.36. My 5th gear is a .72. Is anyone running these combinations that could give me some idea of mileage and performance?

    Thanks for the help. Bill
  2. I'd stick with the 3:55 before I went numbericaly lower.
    Actually I'd look at going higher with that combo.
  3. 327Eric
    Joined: May 9, 2008
    Posts: 1,528

    from Diablo Ca.

    I had an o.t. chevy truck with a set of 3.08's in it, and 32 inch tall tires. Swapping to 3.73's improved both my performance and economy. I'd look at maybe getting a set of 3.73's, or 4.11's with that t5.
  4. Tony
    Joined: Dec 3, 2002
    Posts: 7,350


    When i built my old 53 chevy, i used a 235, T5, 56 chevy rear with the 3:36 gears.
    On the highway it actually lugged at 60 mph. Cant remember the exact rpm but it was under 2k which was great for the life of the motor.
    But, around town it could have really used more gear.
    I really think both mileage and performance suffered with the higher gearing.
    If i did it again id either run 3:55 or 3:70, with my choice being the 3:70.


  5. indyjps
    Joined: Feb 21, 2007
    Posts: 4,164


    What makes you wanna go to a 3.08 or 3.36, mileage?
  6. ebfabman
    Joined: Mar 10, 2009
    Posts: 675


    A lot to consider here. How is the engine built? How tall are the tires. A .72 is an overdrive gear. 3.55 x .72 is 2.56 final drive. Unless you are running a short tire, you're gonna lug that 6 cyl. A 3.73 may be a better choice depending on the rest of your set up.
  7. tjet
    Joined: Mar 16, 2009
    Posts: 1,272

    1. Early Hemi Tech

    Lower highway gears can put a strain on the motor. Lugging a motor with any load will hammer the main bearings to the extent that the bearing half end will squeeze in & contact the crank surface

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