ITT i track my mpg.....cause it sucks!

[blackbeaSSt]

filled up just now with roughly 14.25 gallons with the odo reading 29704

something just doesn't seem right to only be getting 9-10 out of my q-jet 305.

i'll keep track as i hit the quarter tanks and half tank along with miles driven

[tucsonjwt]

In my experience, 9-11 is typical mpg for these old squares in city driving. 13-15 highway mpg is what I would expect - less with towing or heavy loads. A big heavy non-aerodynamic vehicle does not get good gas mileage. A 1/2 ton truck in perfect condition with highway rear axle ratio and careful driving can improve 2-3 mpg. On newer 1/2 ton pickups, I got 19-20 mpg with a 2000 Silverado V6 work truck, and 15.5 mpg with a 2010 Sierra ext cab 4.8L V8 - all city. Like the car ads say: "your mileage will vary."

[blackbeaSSt]

i hear ya tucson! i have seen some people with 383's+ getting better around town then mine so i thought i would just track what all im doing and see if someone sees something that im not.

while i can go about 2 weeks on a tank of gas, i only drive it maybe 20 miles or so per day, never bark the tires, rarely get it over 50mph, and do no hauling! maybe i am doomed with 9-10 mpg LOL!

[Restrorob]

Best I ever got out my 74 350/350 2bbl is 10 with fresh carb rebuild and FULL tune-up, I figured if it's gonna suck gas I may as well build it a little nasty to make me feel better about it....

[71swb4x4]

tracking 1/4 and 1/2 tanks is really unreliable, it would be best to simply track the gallons and mileage each time you fill up, that will be much more accurate for you.

[blackbeaSSt]

Originally Posted by 71swb4x4

tracking 1/4 and 1/2 tanks is really unreliable, it would be best to simply track the gallons and mileage each time you fill up, that will be much more accurate for you.

nah i won't be calculating mpg at those times, just updating with miles driven and how long it takes to get there

[silvereagle07]

Wow, I thought they would get better mpg's than that. I get 15-18 with my TBSS 6.0L with 4.10 gears no matter how I drive it. I'll have to check my old swb to see what it's getting.

[74chevy4x4]

My 74 K20 with a SBC350, XE268 Comp Cam, 700R4, and 4.10 gears only gets about 10-12 in town dpending on how heavy my foot is
Most of what I've read is pretty close to that. Of course, if we were looking for great mileage, we wouldn't be driving Old Square Bodies, would we???

[75ChevyGuy]

My truck get's around 18 for city. Never take it on the highway. I've got a 350 with a quadrajet and a 3l80. I've got 3:73"s in the rear I believe and 15x8 Rallyes with 295/50's on them. And I'll even gun it from time to time. I was getting about 15MPG before I did a tune up with all ACDelco parts. Maybe all you need is a good tune up?

[blackbeaSSt]

Originally Posted by 75ChevyGuy

My truck get's around 18 for city. Never take it on the highway. I've got a 350 with a quadrajet and a 3l80. I've got 3:73"s in the rear I believe and 15x8 Rallyes with 295/50's on them. And I'll even gun it from time to time. I was getting about 15MPG before I did a tune up with all ACDelco parts. Maybe all you need is a good tune up?

see this is what throws me for a loop. you got a bigger engine yet you are almost doubling me up on mpg?

what kinda parts did you tune it up with?

[Your41Plague12]

****, I get like 5.5-6 around town and like 7 or 8 on the highway. If I wanted something with better fuel efficiency, I wouldn't be driving something 8 feet tall with the aerodynamics of a brick.

[blackbeaSSt]

Originally Posted by Your41Plague12

****, I get like 5.5-6 around town and like 7 or 8 on the highway. If I wanted something with better fuel efficiency, I wouldn't be driving something 8 feet tall with the aerodynamics of a brick.

don't get me wrong im not complaining, im mainly trying to get an idea if something is wrong or needs to be replaced

[blackbeaSSt]

i hit a half tank this past saturday at mile 29787. so thats 83 miles on a half tank. best case i'll hit 160 on a tank which would be 11mpg. better, but still wondering if something is up

[Hulk Will Smash]

I had a '78 Bronco 4x4 with a 400M that got 6mpg. Now I have a crew-dually with a 454 that gets 6mpg. Somehow that makes me feel better.

I too scratch my head when I see a really wild range of MPGs for similar trucks. Maybe best to just add them all up and divide by the number of people who tell you their milage. Heck throw out the highest and lowest internet truck milage and then average the rest? Maybe a good baseline.

[dswancutt]

I got 15mpg on the road with calm wind conditions, 11 fighting a 30 to 35 mph headwind this weekend. That is a 78 1/2 ton, 350/350 combo with 3.07 gears and not tuned as good as it should be.

[Greenlee]

Back in the day when these trucks were new, I remember hearing the argument that the 350 actually got the same or better mileage than the 305 because the 305 was underpowered for the truck. I never liked the 305 because it seemed like it had no advantages over a 350.

I used to own a single cab 1988 GMC (newer body style) with a TBI 350 and it got great gas mileage. I'm pretty sure it got better gas mileage than the Nissan Titan daily driver that I own now. After the 88' GMC and before the Titan, I had a Nissan Xterra and I remember being really disappointed with the Xterra because I was expecting it to be a fuel miser compared to my truck that was 12 year older. If I remember correctly, my 2000 v6 Xterra and the 88 GMC both got in the neighborhood of 17 mpg.

[Srubydo1986]

back when i had a modern 350 with old school 350 trans i was getting 15-17 mpg believe it or not.

[redneckchevy]

My DD is a 86' C-10 with 350/700r4 and i get 12 if i keep my foot out of it, but I avg 9 to 11 MPG. If i take it on a long trip i can get 14-15, the best i have ever got was 16 MPG. Its starting to hurt with the gas prices the way they are tho!

[motornut]

If i wana save gas ....I drive my car
If i want comfort or space the truck
I don't count "mpg" I just count how many miles to the next gas station lol

[James McClure]

84 K20, 350 eng, 465 trans, 3.08 gears. 15 to 17 mixed driving. 14 to 15 pulling 7000# trailer. I set timing at 14DEG. Will ping if I step down hard though. I rebuilt carb and leaned it out a bit. Choke is set very light. I also drive conservitivly and use every trick in the book to save fuel. Coasting and drafting mostly. jim

[Shyguy]

Here is something some people do not make sure is if the speed-o-meter is correct. We have a tendency to put non-stock tire sizes on our trucks which throws off the speed-o-meter and the mpg calcualations.

Neither of my trucks read the correct speed.

[Hulk Will Smash]

Calculated 5.37 mpg at my fill up yesterday. Its probably a bit better than that because of the tire diameter difference shyguy mentioned. But, probably not much better. Don't give a crap though, I love my truck!
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[blackbeaSSt]

ok so i didn't even make it to the 160 on a tank mark! hell i only was able to go 131 which comes in a tick over 9mpg

again not that im complaining because i knew going in to buying this truck that it would suck. im just bumfuzzled about the bigger engines getting better mileage. oh well!

[jitteryguy]

my '87 Crew cab dually with a 454/TH400 4.11 gears. it was get'n 8.5 in town and bout 10 interstate,
I recently put a CompCam's high energy cam/lifter kit (260 dur./.475 lift) I havent been home to see what it's get'n city now, but I got 13/14 highway when I was on R&R and that was driven it pretty hard . I'm gonna go with a 700R4 and 3.73 gears and be happy with it.
I just stare at my new wheel's while I'm fill'n up so I dont notice how fuel I just bought !

sad thing is I have a '88 S10 (305/700R4) that get's bought 20 city but I still drive the dually more.

[rayfinseats]

Try new ac delco parts, cap, rotor, plugs, wires etc and bump your timing up to where it pings under load and then bring it down a few degrees till it stops pinging. Probably about 8bdc at 1000 rpm. We did that on my 90efi and got about abut 1/3 better milage.