What kind of fuel mileage do you get?

[2quick4u]

As stated in banner, looking for comparisons.
Please post fuel mileage, and current combination.

Mine:
78 GMC LWB 4x4, vortec headed 350, Qjet, headers, 31's, and 3.42 gears 12 MPG best avg 50/50 city hwy

84 Crewcab dually, 454, TH400 w/ Doug nash 2-speed OD. Qjet, SP2P, headers, CompCam 252H, Allison convertor, 4.56's (I run an A/F meter on this one) 12 MPG hwy. This is my hauler.

81 Crewcab SWB (3/4 to 1/2 ton conversion) Fresh 454 , TH400, 2.73's, 16-17 on hwy (honest) Latest project that I am thouroghly enjoying.

I build and Tune Qjets as a hobby, and looking for info on other setups.
Also My 80 SWB hotrod, 8/71 Blown 540BBC, TH400, 4.56's, 2-950's, etc 2-3 MPG at 50mph. Drove to a local show 15 miles (longest drive its been on in 15 years) round trip, and my 15 gal fuel cell was empty.

 

[Green79Scottsdale]

1979 K20, stock 400sbc, TH400, 3.73, 31's... 10mpg

 

[DoubleDingo]

I took mine on a good trip a couple years back and it averaged 8 mpg which was very disappointing to me. But with 4:10's I hear it is to be expected. Since that trip I have done some upgrades, and each time I have wanted to take the truck on another long trip, something has happened so I haven't been able to get new numbers.

Soon, I will be able to take it on another long trip so I can report back what numbers I get. I do know the around town mileage has greatly improved over what it was before the improvements, so I am optimistic the highway numbers will be better.

 

[cramezl]

1986 GMC 3/4 ton 350/465/208 4x4 in need of a tune up- 7-8mpg

 

[foamypirate]

TBI 305
TH350 w/ 2200 stall
3.08s
2wd

9.6MPG, all in town, and I have a lead foot.

 

[Old77]

350 GM crate motor
holley 650 cfm carb
headers, true dual exhaust with flowmasters
TH350 w/2200 stall
3.08 gears
2wd

10 mpg on a good day but I have a heavy foot and love the roar so it's a bit less than that normally I'm guessing

 

[Gmule]

1979 K20, stock 400sbc, TH400, 3.73, 31's... 10mpg

Same here with a K-10 with a 350 / 350 3.73 and 31X10.50 tires

 

[Green79Scottsdale]

I don't feel too bad about mine now...

 

[Boone83K10]

83 K10 350 Holley 4175 spreadbore 700r4 3.08 10 bolts.. lately I have been consistently over 9 mpg since I last tuned the carb. This is the most it had ever gotten. Not to bad for all mountain driving at 3600 feet.

 

[da_raabi]

1986 C30 crew dually: 454 (needs a tune), TH400, 4:10s, brand new 235/85r16s. I get about 6-7 all day long running all city driving. I get maybe 10-11 highway. People think I'm joking when I tell them I get 6mpg lol.

Thats why I love my sticker in the rear window: "My carbon footprint is bigger than yours!"

Even though its not - but I wont go into that here.

 

[GTME94]

1986 C2500 Reg Cab, LWB, Camper Special, Stock 454, TH400, 3.73

10 MPG Highway

 

[Gmule]

83 K10 350 Holley 4175 spreadbore 700r4 3.08 10 bolts.. lately I have been consistently over 9 mpg since I last tuned the carb. This is the most it had ever gotten. Not to bad for all mountain driving at 3600 feet.

I would think that with 3.08 gears and an overdrive transmission you would get around 15

 

[350runner]

82 LWB, 2wd, 350 tbi, 700r4, 3.08s, 31s, q jet, 17.5mpg hwy

Sent from the dust in front of you!

 

[slowlane]

1985 C20 with a 1975 350ci, holley 670 street avenger, TH400, cobbled dual exhaust, 4.10 rear. I get about 12.5 average, but I drive pretty conservatively and only cruise at 60-65 on the highway.

 

[Stewzer55]

2007 Chevy Trailblazer 4x4, 4.2 I6, 4L65e 3.42 gears, 245/60-17 tires 14.5 city, up to 21 on the highway at 70.


I expect a high of about 12 MPG in my square with the TBI350, TH400 and 4.10 gears.