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Miles Per Gallon

Discussion in 'The Garage' started by Justin Fleming, Sep 29, 2005.

  1. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    How many miles per gallon should a stock 305 k5 (carb) get? I just got this truck and have finally got everything sorted out but man the Gas mileage seems horrible. It is getting 300 miles to the tank. :confused:

    thanks
     
  2. randy88k5

    randy88k5 1/2 ton status

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    Thats roughly what mine got with 2.73s and a 31 gallon tank. Driving around town killed the milage. Highway was decent. Id expect a properly tuned carb should get you in the neighborhood of 12 mpg on average. EFI being a little higher, around 12-15 mpg.
     
  3. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    Well I guess I am right in the ball park then....Thanks for the info......This last tank I got about 100 miles around town and 212 on the highway....
     
  4. MTMike

    MTMike 1/2 ton status

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    A buddy of mine has an 85 K10 w/ a stock carbed 305 and a 4 spd and claims to get 16-18mpg with it.
     
  5. zeroz400

    zeroz400 1/2 ton status

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  6. diesel4me

    diesel4me 1 ton status Premium Member

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    eggs..

    I can squeeze 15 mpg out of the 86 305 in my 79 C10 2wd pickup with an 8' bed empty..it has a 600 CFM Edelbrock Performer carb--I bet if I'd put a Q-Jet on it it would be a bit better,since the primary barrels are smaller..a 2 bbl would be a bit better too I'd be willing to bet..15 mpg seems to be about the limit to the mpg you can get with a 4 bbl if you keep you foot out of the secondary barrels..my 400SB in another 4x4 truck got 13-15 mpg with a Carter 625 CFM carb!..and the motor was old and tired too..

    Best mileage I've gotten from any chevy small block was a 1967 283,with a 2bbl, I had in an Impala..got 18-20 mpg,it had a Powerglide tranny and 3.08's..I've heard of shortbed pickups with the same setup getting over 20 mpg if driven carefully..

    You need to drive like an egg is between your shoe and the gas pedal and try not to break it,if you want good gas mileage..anticipating stops,and pumping your tires up to 35 psi helps too..and make sure the timing is set right--I advanced mine few degrees past stock settings until it pings slightly,then back it off just enough to stop it..adds 3 mpg in my case--and I found using manifold vacuum to the distributor helped on my 305 too.. :crazy:
     
  7. bigbadchev84

    bigbadchev84 1/2 ton status

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    wow you guys get miles to the gallon? as quick as my gas gauge moves i think im only getting ypg...Yards per gallon!
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    STOCK 1983 K5, 305/700R4/3.08/31" tires, typical 17MPG freeway, in town always varied 10-13.

    Freeway was cross country loaded with at least additional 750lbs, so it might have gone up a hair had it been empty.
     
  9. gjk5

    gjk5 3/4 ton status

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    I think in my '72 K5 with a 350/TH350/3.73's/33" tires and edelbrock performer I get around 5-7 MPG. :(
     
  10. anjieandjohn

    anjieandjohn Registered Member

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    I usually get around 12/gal intown and 17-18 on the highway doing 75...probably would get better mileage if I slowed down but who really gives a crap about the .2 gallons I might save...My truck is stock with a stock carb and has 221K miles with no rebuild...leaks a little oil but that is to be expected...
     
    Last edited: Sep 29, 2005
  11. neubanksc5

    neubanksc5 1/2 ton status

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    Just figured mine up....87 k5 4" lift 33" bfg mud terrains and 3:73's = 12.2 mpg
    that was with about 160 miles highway and and 160 miles in the city. just cost me $75 to fill it up
     
  12. thfonz98

    thfonz98 1/2 ton status

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    stock 91 k5 350/Auto 3.73 31" bridgestone revo a/t: about 1/2city 1/2highway (75-80mph and heavy foot)14.5-15mpg (speed limit/ slow off the line) ~16-17.....thats what ive measured
     
  13. chevydan3

    chevydan3 1/2 ton status

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    1982 K20. 350, Al stock except Edelbrock EPS 600 CFM, Dual 2-1/4 Exhaust, Rebuilt Heads, 700 R4, 4.10's and 35's and I get 7.5 MPG. I don't understand how you guys get 15-16. I am sure that the aerodynamics of my 8 inch lift suck, is that my whole problem.
     
  14. diesel4me

    diesel4me 1 ton status Premium Member

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    big tires== low MPG..

    Those big tires are heavy,and have a lot more rolling resistance than skinny stock tires..you DO gain some MPG by increasing tire size to a degree--it acts like an "overdrive"--its like making 3.73's feel more like 3.08's when you go 2-3" bigger diameter..but the weight and rolling resistance kills a lot more than you gain..and your right about areodynamics..our GM trucks are mor like a brick, than a missle as far as wind resistance..and lifting them only makes things worse..I'm suprised we CAN get 15 MPG out of some of them!.. :eek1: :crazy:
     

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