Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

bad mileage???

Discussion in 'The Garage' started by 85mudblazin, May 18, 2004.

  1. 85mudblazin

    85mudblazin 1/2 ton status

    Joined:
    Mar 26, 2004
    Posts:
    3,951
    Likes Received:
    0
    Location:
    Austin,TX
    I have this 350 and my problem is that I only get about 7MPG per gallon, I have the stock carb and intake, with headers, does anyone know why I get such bad mileage?? This is the 350 that I have
     
  2. 4xcrazy

    4xcrazy 3/4 ton status

    Joined:
    Oct 31, 2003
    Posts:
    9,472
    Likes Received:
    5
    Location:
    Olympia/Lacey, Washington
    I get 10 in my Burb around town, but mine is also fuel injected.

    oh, the other thing,,,5000+ pound vehicle your tryin to move there.
     
  3. 85mudblazin

    85mudblazin 1/2 ton status

    Joined:
    Mar 26, 2004
    Posts:
    3,951
    Likes Received:
    0
    Location:
    Austin,TX
    yeah that is tru but I thought I would get a little better than 7MPG /forums/images/graemlins/doah.gif
    Also I have 35" tires and I was wondering if changing out my gears would help my MPG any? I am think about getting 4.56 gears.
     
  4. mtnman210

    mtnman210 1/2 ton status

    Joined:
    May 30, 2003
    Posts:
    3,880
    Likes Received:
    0
    Location:
    Northridge, Ca
    I'm running a gm crate 350 with a holley 600mcf card. I've got a 6in lift with 35 bfg mud/t and 4.56 gears i very between 7-9 mpg. so really you're right about where you mileage will sit. maybe changing gears might help a little but not much.
     
  5. 87BrnRsd

    87BrnRsd 1/2 ton status

    Joined:
    Apr 21, 2003
    Posts:
    2,457
    Likes Received:
    0
    Location:
    Boone, North Carolina
    4.56's and 35's will suck gas around town and on the highway unless you have od. I am running 37' mt/r's with 4.56 gears and a 700r4 od tranny, plus I have tbi fuel injection, and I still average about 8 mpg around town. Highway is a little higher, maybe 11-12? As stated above, your trying to move a 5000lb+ truck, that is about in the shape of a box. Not very aerodynamic, and 350's in our blazers arent the most efficient engines on the market...
    BTW what gears are you running now?
    -Harrison
     
  6. scoutillac

    scoutillac 1/2 ton status

    Joined:
    Feb 24, 2004
    Posts:
    423
    Likes Received:
    0
    Location:
    Spokane, Wa.
    I am barely getting 10 in the city with a fresh rebuild. I do have a bigger cam, K&N, TB spacer, and Jet chip. I am hoping to get a mile or two more when the engine gets broken in. I also have 35's and 4.56's 350 tbi 700R4 np208 blah blah blah
     
  7. ratzila

    ratzila 1/2 ton status

    Joined:
    Aug 9, 2003
    Posts:
    691
    Likes Received:
    0
    Location:
    Mobile,Al
    I have a 454 with bigger cam,800 cfm quadrajet, headers,th400, 5.13 gears & 44" boggers and it gets 8 mpg on the interstate /forums/images/graemlins/woot.gif
     
  8. 85mudblazin

    85mudblazin 1/2 ton status

    Joined:
    Mar 26, 2004
    Posts:
    3,951
    Likes Received:
    0
    Location:
    Austin,TX
    I have the stock 10 bolts front and rear but I dont know what gears they have in them, what ever is stock is in there. /forums/images/graemlins/thumb.gif
     
  9. Bhintz

    Bhintz 1/2 ton status

    Joined:
    Mar 28, 2003
    Posts:
    1,341
    Likes Received:
    0
    Location:
    Roswell, Ga
    if you want new gears I would just upgrade the axles to 10/14 or 44/14 b/c its about a grand cheaper and you get the gears you want and more strength and if your running a 350 or 400 trans Id go with 4.10s and not 4.56s
     
  10. darkshadow

    darkshadow 1 ton status

    Joined:
    Dec 6, 2003
    Posts:
    12,250
    Likes Received:
    0
    Location:
    C-eh-N-eh-D-eh
    [ QUOTE ]
    I have a 454 with bigger cam,800 cfm quadrajet, headers,th400, 5.13 gears & 44" boggers and it gets 8 mpg on the interstate /forums/images/graemlins/woot.gif

    [/ QUOTE ]
    Ratzlia i love you truck all the more /forums/images/graemlins/bow.gif /forums/images/graemlins/bow.gif /forums/images/graemlins/bow.gif

    Thats impressive for your beast
     
  11. gravdigr

    gravdigr 1/2 ton status

    Joined:
    Apr 15, 2003
    Posts:
    1,129
    Likes Received:
    0
    Location:
    Tyrone, PA
    [ QUOTE ]
    and 350's in our blazers arent the most efficient engines on the market...

    [/ QUOTE ]

    The 305 is even worse. I might pull 10mpg with my 86 carbd 305 but with the mountains here it's usually closer to 7-8. I'm installing a 350 in hopes of getting better mileage.
     
  12. ratzila

    ratzila 1/2 ton status

    Joined:
    Aug 9, 2003
    Posts:
    691
    Likes Received:
    0
    Location:
    Mobile,Al
    When I had the 39.5 tsl & sm465 it would only get 6 mpg.
    Switching to the t400 & 44's lowered the rpm's and raised the mpg's. /forums/images/graemlins/thumb.gif
     

Share This Page