What is the best milage anyone has got out of a 350 in these trucks?

[ubtripn]

I know gas mileage is not why we own them but I am still curious. If you could maybe include the gears and trans used too if possible. Thanks.

[chevelle]

19 MPG!! haha its not great but im pretty proud of it. its a 350 tbi fuel injected, with a 700r4, with 3:73 gears

[Bad70sbchevy]

11mpg with a good tailwind driving down hill, but mines not exactly set up for gas mileage. I am kind of curious what everyone else is getting too.

[67swb72klb]

Originally Posted by chevelle

19 MPG!! haha its not great but im pretty proud of it. its a 350 tbi fuel injected, with a 700r4, with 3:73 gears

what year motor ? just taken out bbc in the 67 not shure what i want to go with was thinkn lt1 mabe

[ubtripn]

19 is not bad at all. That is what my wife's Subaru Outback gets!

[Indyuke]

17mpg on the highway. It's got a q-jet, 700r4 and 3.73 gearing. 2wd

[ubtripn]

I would take 17, I heard a well tuned q-jet will get the best mileage/power combo of any carb out there but that's probably another thread.

[sanford66]

My 68 is about 10mpg on the highway. Thats with a mild 350, th400, and 3:73 gears. But i love every minute of the gas guzzling fun, MPG....who cares!! It's all about the smiles-per-mile! Joseph

[capev86]

yes, a properly tuned q-jet gives you the best of both worlds. the primaries in a q-jet are smaller than the 2 bores in a rochester 2bbl. gives awesome throttle response and economy as a result. and you have those huge secondaries for when you need power. why anyone would ditch one in favor of a square bore is beyond me. they ran q-jets on muscle cars. guess people just get excited by brand names and figure they are automatically better than factory. only thing better than a q-jet is a tbi as it gives similar low end efficiency but gives you automatic adjustment for changes in altitude, etc. you can use the 454 ss unit on a hogged out small block tbi manifold if you need high end power too.

i was getting 10-11 in mixed driving in my 72 burb c20 307 2bbl 3 on the tree w/ 4.57 rear gears. i did the 4:10 swap and it should be getting 13-14 by now. i did also upgrade to an edelbrock performer (idle-5500rpm) intake with a q-jet on top to try and wake up that 307 i picked up a 66-69 borg warner o/d equipped saginaw for my truck and hoping that gets it up close to 17-18. still have that 406 and gonna need the o/d when i put it in my truck. my dad's 72 burb c10 w/ 350/350 combo and 3.73 rear used to get 15mpg solo.

17-18 on the highway w/ 350 q-jet, 2wd, 700r4 and 3.73 gears is what you should expect. that's what my dad's 84 burb used to get with that exact combination. we averaged 19 on one tank by keeping it under 60mph on a long highway trip. and that was with low compression on one cylinder and over 100k on the original engine. we dropped in a 406sbc with the 350's q-jet and intake swapped over and got 16-17.

in contrast, my dad's 99 burb 1/2 ton 2wd with fuel injected 5.7 consistently gets 22mpg on mixed driving (including some tow truck duty). thank the 3.42 rear and aerodynamics for that. it still has a 5500 pound tow rating and pulled our 6000 pound '71 Holiday Trav'ler down to my house from my grandmother's 2 hours away. my burb stil isn't quite ready for big towing duties yet.

[DT1]

71 350/350/3:73/RV cam/Stock Q-jet/Fresh engine.
When this thread started, I would have stated 10MPG HWY.
Yesterday I filled up with good'ol 87 Oct. and drove 130 miles over a mountain road. I was surprised (Happily) to get 16 MPG!
That's more than 50% better than expected!

[406 Q-ship]

67 C10 short step 350/th350 3.08 gears (not sure on the gear ratio). 17-18 MPG mixed driving between freeway and city streets. I was very impressed. My old 1974 C10 short step 350 goodwrench / 700r4 with 3.73 (might have been 3.42 can't remember what was in the truck at the time) and it knocked down 17 MPG with only freeway driving to San Diego.

As a side note I just drove my 1968 Chevelle to Florida from Los Angeles and it gets 19-21 MPG. It has a 350 / 330 hp crate engine with a Comp Cam 268 and a Edelbrock 500, a TKO600, and 3.31 ratio

[special-K]

I get 12.5 in my '72 GMC K2500 350 4bbl/TH350 3.54:1

[Robertjust777]

ya i get about 7 mpg in my truck ahhha! if that not counting my heavy foot. aluminum heads th350 3.73 holley dp