gas mileage?

Discussion in 'Performance, Engine, and Transmission' started by skirk, Jul 16, 2009.

  1. skirk

    skirk Member

    Joined:
    Jun 25, 2009
    Messages:
    28
    I am running a stock 250, single barrel holley carb. 66 chevy long bed. the gearing seems to be kinda low, everything is factory original. what kind of gas mileage should i be getting, and what things could i do to improve it any? btw thanks to all who sent info with my points question all seems to be running smoothly now.
     
  2. drabo

    drabo Member

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    Jun 9, 2003
    Messages:
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    Location:
    Patrick AFB, Florida
    Not sure on your gas milage but I'm sure it's not that great. However if you want to greatly improve it you can do two things put a 700R4 tranny in place of the old tranny or 5 and 6 speed manual. Next is to change the gearing. The economical swap is 3:73's otherwise you will need to change out the carrier and the gears. You will find that you probably have 4:10's right now. www.bowtieoverdrives.com is a good place to start a 700R4 swap. It will help you figure out what you need. It is easy to do and can be done in a day. If you have a powerglide in there now it will require the the driveshaft is shortened about 2 1/2" and then rebalanced. It costs around $100. It will be a good time to change out the carrier bearing and the u-joints.
     
    Last edited: Jul 22, 2009
  3. TCain

    TCain Member

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    Jun 23, 2007
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    well i dont know you maybe like me and have a 3 on the tree and don't want to have to change alot of stuff out to get better mpg but there are different intake and exhausts you can use to get better mpg and try rebuilding your carb i did and i got about 2 more mpg
     
  4. coilover

    coilover Member

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    Mar 30, 2005
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    Location:
    Plano US
    I used a Borgwarner OD on a 68 and jumped the mileage from 12 to 16. It was an option when these trucks were new and fits right in place of the regular 3sp. If you have a 4.11 rear the final will be 2.88 in OD or if the rear is a 3.90 the final is a 2.73 in OD. I see them at swap meets for in the $125-$150 range. Not as sexy sounding as a 5sp but at least as strong as the wimpy S10 5sp and bolts right up to where the 3sp was. Better gear ratio at a full 30 percent OD than that of the wimp also.
     
  5. mikeslaves

    mikeslaves Member

    Joined:
    May 24, 2010
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    1
    I completely not to know about that but I simply agree with the given suggestion by the reply.I think by that suggestion you get solve your problem.
     

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