I'm getting about 16 mpg (imperial gallons) with mine. 5.8, 4X4, 3.55 limited slip rear end, LT235 75R15 tires. That's highway mileage, doing about 55 mph. 70 mph, will drop mine to about 10-12 mpg. Makes me wonder when guys blow past me on the highway, who's paying their gas bills. If the truck you're looking at has a 4 speed automatic, you should quite a bit better mpg than I do. My buddy has a 91 F150 with a 302 and a 4 speed automatic. He says he's getting around the 20 to 23 mpg area, (imperial gallons) driving at the same slower speeds as I do.
My truck is a 1993 F150 2wd with a 3.55 no limited slip diff stock tires wheels all tuned up and i drive with a light foot im guessing rpms dont exceed 2000 i get 14-16 mpg mostly city with some freeway ill have to actually check my mileage one of these days
Dont expect good especially with 4x4 only mods on my truck would be 2.25 custom dual exhaust with flow 40s
I have a 95 F 350 4x4 with the 5.8 and I get 11-13 no matter where I am driving as long as it is empty. I get about 11 city and 12-13 on the highway at 70. It has an E4OD auto w/3.55's, and it weighs about 5900 lbs. I know most of you that have replied have 1/2 tons, but I thought I would throw mine in for comparison.
well my 96 i get around 12-16 agian depends on how its working . mines just what your buying supercab, short box e4od , 5.8 3.55 , i am runnign 32s right now. now, i just installed the k&n cold air kit. and boy i noticed a huge improvement power and fuel wise . its a drastic difference . (the kit advertises like 10 hp on a 5.0 at 4000 rpm)
My '92 with 5.0, M5OD, and 3.08 pumpkin will reliably turn 19 mpg highway, and around 13 city. The 13 city is because OD is too high for city driving, and I stay in 3rd/4th most of the time. This is with 152K on the original engine. BK (Before Katrina) it would reliably turn 21 mpg highway. I think fuel quality has suffered tremendously with the much higher exhorbitant prices.
I'm thinking the 5.8 in front of the same drivetrain would do about the same, maybe just a little less, again, depending on how much I tickled the skinny pedal.