6'' lift w/ 35'' tires affect on MPG?

[bluto1all]

Okay, so my Chevy 77 K20 Camper Special had a 6'' lift with 35'' tires on it when I bought it.  I love the stance of it with this setup, bt my MPG is horrendous (about 6 MPG give or take). I already know the carb needs to be dialed in (maybe even replaced, it's currently running an 80 Corvette carb) but how much MPG will I be losing if I stick with the 6'' lift & 35'' tires?  2-3 MPG? More?

Should I pull the tires & sell them (they are in good shape) and go with some 33s or even 31s?

Need some advice...thx!

[spectreblazer]

i get 6 with 8" of lift and 35s. all you can really mess with is your gearing, engine tuning and tranny

do you have an overdrive trans or a 350:400.

[bluto1all]

Ugh!

Tranny is just a TH350.  Pretty sure the rear end is supposed to be 4.10 (right?).  Don't have any reason to think it's anything but...

Would I benefit from going with a smaller diameter tire.  Tuning & carb work are a given & I will be doing that.

[bake74]

     The only thing about lifted vehicles are the drag they produce from being up in the air more, but you can not get away from that.  The other option you might want to think about is switching tranies to a 700r4, would not be that hard and would give you overdrive.

[79 chevy]

i was wondering to my truck dont have overdrive if it did how much would that gain me on mpg.??

[bake74]

     Depends on how much highway driving you do, around town in stop and go traffic it will not help too much. 

[Irish_Alley]

I got 38s with 4.10 and a 350/sm465 i get 11. Change of driving habits will do wonders be I changed mine I was probably about 8

[bowtieman82]

I have a 82 with 33 and 3.73 with the sm453, 350 that is put out like 350 to 400 and i get 16 on the high way as long as i keep my lead foot out of it, in town i get 12. i have change the card, the intake, cam, and exhaust.  i have a demon 625 card, a STRIP DOMINATOR INTAKE MANIFOLD, and MSD HEI coil and Mr Gasket Adjustable Vacuum Advance, MSD Ignition Module, Mr GasKet High Performance Spring and Weight. A Lunati Voodoo cam. My exhaust is 2" with 3' long glass packs, and a set of flow tech headers. My truck run great. I want to to a over drive unit on it sometime when i get 2000 for it.      

[Lt.Del]

having these 35 and 38" tires on these trucks is really like putting an OD in your truck....If you put OD on a truck w/ 35" tires, that truck may seem to bog down at highway speeds and you'll use more gas because your foot is deep in the accelerator all the time to keep it going.

If you mainly do city driving, the truck will be a dog---seems to take forever to get her up to speed the bigger the tires, using much more gas.  If you want that giddy up and go effect, use smaller tires and you'll find you're using less gas.  I just think OD with monster tires is not the answer, you'll find that on highway speeds, the OD will be kicking out on the slightest of hills because of the TALL gearing caused by the tires and OD. Your foot will need a rest from pressing that accelerator so much to keep her at speed.

I've got a 4x4 5.7 sub w/ 33's and 3.73 w/ 4l80e OD trans.  The gearing is a tad tall for my liking.  Never going w/ any bigger tires.  I have a set of 265 tires/wheels which is about the same as 33's.

[Irish_Alley]

you have to up the gearing to make up for big tires. so lets say like sgt he has 3.73 i would like that with a nv4500 good low gears to make up for the tires then od

[Edahall]

The lift won't affect fuel economy so much if you keep your speeds down.  I've got a lift on my Suburban and as long as I keep it under 60, I get excellent fuel economy.  At 85 mph, it uses almost double the fuel.  With the astronomical fuel prices, I have been keeping my speeds on this vehicle down to 55 mph and with the Cummins diesel under the hood, I'm able to squeeze nearly 30 miles per gallon.  Once my wide tires wear out, I'm going to go for some tall and skinny tires and see what that does to fuel economy.

[Cheyenne]

What size tires are good on 15 inch rims lift or no lift for really good gas mileage?

[Irish_Alley]

[Psycho71]

cool chart. what kind of mph does that represent? From the rpm ranges, I'm guessing 65mph.

[Irish_Alley]

yes 65