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Gear Ratio (3.07)?

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by Robin, Jun 3, 2002.

  1. Robin

    Robin 1/2 ton status

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    How common are 3.07 gears? I have this tab on one of the front axle bolts that claim this ratio. It's this a little high?
     
  2. Goober

    Goober 1/2 ton status

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    During the 1970's gas wars lots of trucks had these "weenie" gears in them.

    Great for gas milage ... rotten for anything else.
     
  3. blazerboy72

    blazerboy72 1/2 ton status

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    i have 3.07 but if these are good on gas mileage ai am in big trouble. I only get 3-5 miles per gallon it is about time to start measuring in gallons per mile
     
  4. 70~K5

    70~K5 1/2 ton status

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    but they put the 3.07s in truck with 29" tires too. What size are you running?
     
  5. ed rex

    ed rex Registered Member

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    My Jimmy came stock with the 3.07's. It was manual. I was under the impression that the 3.07's were the gears you got with a manual tranny.
     
  6. Robin

    Robin 1/2 ton status

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    My sentiments exactly, but I get 10mpg @65mph. I went down to 31's so the truck wouldn't be so doggy. Helped a little, though hopefully with the new 388, I'll have the response I'm looking for and "decent" mileage....
     
  7. Steve_Chin

    Steve_Chin 1/2 ton status

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    My '72 Blazer was also originally a 4-speed truck and has 3.07:1 cogs (like my buddy's '72 Blazer). I get ~14 MPG on the highway with 32s. The 5-speed made virtually no difference in gas mileage (none measurable, anyhow), but it makes driving the thing more of a pleasure.
     

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