I'm looking for a newer truck, probably a 96-up K1500 shortbed or K2500/3500 longbed. What kind of mileage are you guys (and gals) getting in your vortec engined trucks? I'm especially interested to hear from those of you with 454's. If possible, give some details, like tire size, gearing and driving habits... I'll probably stick with the 350 and auto, but if I find a clean big block truck it would be hard to pass up. Thanks...

you wont find big block in 1/2ton, unless you put it there.

most of the 454s will be in long trucks, reg long bed(kinda rare) exstended cab long bed(best chances) ex shortbeds(custom order trucks) dualies will have good chance of being 454.

one thing you will find are gobs of 350s in 3/4 ton trucks backed by the 4l80e auto tranny, this isnt that bad of set up, and can be had in 3/4 ton ex cab short bed trucks. these trucks in there all around drivn probly get between 12-16 on a average with some pulling 18 or better on highway.

my dads
97
2500 hd
2wd
350/ 4l80
373s 245 75 16
14 town
18 highway
driven slow to moderate, but he keeps in in od even in town

I know what the drivetrain combos are, If it's a 1/2 ton it'll have the 350/60e, Otherwise it'll be a 3/4 or 1 ton Reg cab longbed with an automatic. I don't want a dually or a long wheelbase truck. I don't expect great city mileage, but I do a lot of highway driving and would like to see mid to high teens unloaded on the interstate.

I'm telling you this as far as weight considerations go, but on my '99 4DR 4x4 Tahoe I've seen 19 and a little better on the highway, it's stock (almost), no lift, stock wheels + 245-75R/16. My cousin's '97 Sierra Ext Cab Short Bed K1500 with 350/Auto/3.73s/16x8s + 265-75R/16, has been known to get 21-22 on the freeways. We had a '97 K3500 Ext Cab Long Bed Dually with an 11.5" Lance camper in the bed and that thing got 16 or so all stock with the 454. Granted a camper in the bed of that hting was no where near it's capacity, but it is a fair amount of mass to tie to something and go 70mph down the road with.

22mpg highway? How fast do you drive on freeways?

Well I just got mine and drove it very little and it seems it will be a big gas hog, something ain't right... The ses light was on so unplugged it and it never came back. I'm guessing O2 sensors.. But I would suspect the average truck will get 13-18+... Depends on speed, terrain, load and driver.

I think the 22mpg was acheived at a cruising speed of around 76-78mph.

I still don't understand how you can get 22mpg at 76-78 mph, unless its all downhill. When i drive freeway, i go 80 and get 17mpg.

Your grille guard front bumper will cost at least 1 mpg, also, from my experience, tires bigger than 265's will reduce fuel economy as well.