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Gas mileage on carburated 350ci K5 Blazers?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by tungsten, Nov 28, 2003.

  1. tungsten

    tungsten 1/2 ton status

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    Curious as to what sort of in town and highway gas mileage you guys are seeing on your carburated 350ci K5 rigs. This one of mine has a tired old 305ci in it and I figure I'll be pulling that engine and replacing it with a 350 next Spring.

    My logic is that a 350 will pull the weight of the truck a lot easier than the 305 will. But maybe my thinking is flawed?
     
  2. 99firehawk

    99firehawk 1/2 ton status

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    Well with a too big untuned carb and a fresh tight motor I got 147 miles to a 30 gallon fill up. After putting on a smaller carb and tuning it, fixing my timeing airing up my tires fixing some other minor problems I got 370 out of a 30 gallon fill up. Now my choke is stuck and so is my high idle /forums/images/graemlins/angryfire.gif and I got about 80 miles out of my fill up /forums/images/graemlins/angryfire.gif
     
  3. BlazerWheels

    BlazerWheels 1/2 ton status

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    I usually average about 9-11...combined driving. /forums/images/graemlins/grin.gif

    But that is with 3.08's and 31" tires /forums/images/graemlins/blush.gif...
     
  4. blasterD

    blasterD 1/2 ton status

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    I have a K10 Longbed with a 350 sbc, th350, np203 and 4.09 gears with 35" BFG's w/ 6" lift and I get 11mpg Highway /forums/images/graemlins/cool.gif, 9mpg town /forums/images/graemlins/frown.gif and 6-7mpg Offroad /forums/images/graemlins/pimp1.gif. It is a stock long block with an edelbrock performer manifold and 600cfm carb jetted for 5000 ft.
     
  5. tucsonkfive

    tucsonkfive 1/2 ton status

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    10 or 11 mpg regardless of where I'm driving. /forums/images/graemlins/thinking.gif Goodwrench 350, Edelbrock RPM intake and performer carb.
     
  6. tungsten

    tungsten 1/2 ton status

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    Hmmm... are fuel injected guys seeing considerably better mileage?
     
  7. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    With my 83 which has 305, 700r4, and stock 3.08 gears (I'm poor). I get around 15 mpg combined. Oh and I am running 32 inch tires. It's best to keep it tuned right and filters changed. Logic would dictate that as long as both engines are in good order , the bigger one would have an easier job with the extra torque the engine has ( horsepower = torque x rpm / 5252 ). Torque is more important than horsepower in a general all around truck.
     
  8. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    i have a 83 k20 with a 350 with only 600 miles on it with th350/np208 3.42 gears and 265 75 16 and i get 12.5 highway /forums/images/graemlins/eek.gif i will be putting a 700r4 it tommorow and maybe ill get better gallons per mile
     
  9. Okiemuddog

    Okiemuddog 1/2 ton status

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    I am running a TBI 350 block and heads about 90K on the engine with an Edelbrock performer intake and Edelbrock 600CFM performer carb that is well tuned with a 700R4/203 combo/ 4.56's and 36's and I average about 10-12mpg on the highway. That is when I am gentle with the long skinny, if I driving it hard I can get it all the way down to about 5mpg /forums/images/graemlins/eek.gif /forums/images/graemlins/rotfl.gif
     
  10. k20

    k20 3/4 ton status

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    no i saw worse, back when my old tbi 350 actually ran it got about 8 everywhere.
     
  11. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    no i saw worse, back when my old tbi 350 actually ran it got about 8 everywhere.

    [/ QUOTE ]

    Thats funny I get 14 with mine with no OD and 4.10s and 31s. /forums/images/graemlins/rotfl.gif
     
  12. BowtieRed

    BowtieRed 1/2 ton status Author

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    4-5mpg. crate 350- horribly tuned old worn out q-jet.
     
  13. 75-K5

    75-K5 3/4 ton status

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    15 /forums/images/graemlins/deal.gif
     
  14. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    6 to 9 in town, 10 to 13 on the highway, all depending on throttle. I have a pumped 406, 700R4, 4.10's and 35" boggers. Edel. q-jet. Hopefully it will jump up a few with multi port FI. I used to have a 350 and mileage was considerably better than with my 406.
     
  15. RATAH

    RATAH 1/2 ton status

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    8 miles per gal thats all highway driving
    with 35x12.5x15
    308 gears,350 motor,350 trans,205 tcase
     
  16. k20

    k20 3/4 ton status

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    ya i had th400, 4.10's and 33's, but of course w/ a motor that was at that was already knockin and gutless, ya had to tend to stand on the pedal.
     
  17. BayouBlazer88

    BayouBlazer88 1/2 ton status

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    [ QUOTE ]
    Hmmm... are fuel injected guys seeing considerably better mileage?

    [/ QUOTE ]

    No /forums/images/graemlins/frown.gif, at least not this fuel injected guy. 88' K5, freshly rebuilt 355TBI with vortec heads, TES headers, 700R4 that's not in the greatest shape, NP208, stock 3.42s, 31X11.50 AT's, and getting around 11 city. 2 years ago when I bought this tank it was getting around 13 city (before I started taking things apart). But in the K5's defense the EGR system isn't hooked up, the AIR system has long been removed, and she most likely needs a custom chip to run at her prime.
     
  18. 88jimmy4x4

    88jimmy4x4 1/2 ton status

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    Just curious.....but how is a blubie posting in this forum? /forums/images/graemlins/thinking.gif
     
  19. Muddytazz

    Muddytazz 1 ton status

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    More than likely, the post got moved out of the garage /forums/images/graemlins/thinking.gif
     
  20. 75-K5

    75-K5 3/4 ton status

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    His membership must have just expired, because he was orange when he started the thread.
     

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