I have an 05 cc dually long bed with the tow boss package. During my trip 250 mile trip south this weekend I got around15.5 running 80. I have SCT programer running the extreme street..have 4 inch straight pipe exhaust, new intake elbow and new upgraded intercooler. Then I ran a short trip through the woods and got around 16+ running slower. But at 80 my truck is turning around 2500.
Slick I would like to see a picture of your truck. I have an 05 that is about to need new rubber. Did you lift the truck to clear that.

My 04 6.0 crew cab srw gets about 16-18 on the highway empty. Towing, around 10-12. Wind seems to have quite a effect on these trucks. I have turbo back silverline exhaust, with no cat. Sounds cool, but dont think it did a lot for mpg.

Without seriously messing with your truck thats really about it, and the cheapest place to start. You will spend about a grand on all that stuff if you shop carefully. Maybe get 4 or 5 more MPG....maybe.

I used a two and a half inch leveling kit on the front with Brentz Classic wheels that were 19.5x6.75 and Michelin 265/70r19.5 XDE 2s (a pricey modification but has been well worth it to me)with no clearance issues whatsoever, I had tried a set of 22.5s with adapters and pretty much decided that that was a giant waste of money(do a thread search)

Looks good. I know I don't want the 22.5.... Thanks for the pictures, he has some wheels i really like, just waiting till the tires i have are gone before i get new ones. I am pretty sure I want to go that route...just have to save the money for them, in the middle of a kitchen remodel, finish that then get the new stuff.

I have never seen a 6.0 get over 14
mine is a 06 f350 drw auto 4:10 rear 4x4 5" straight pipe sct tuner, drive it like a sports car and get 10mpg in town, 12mpg on highway empty ( 90mph) 9 mpg towing 15000 lbs (80 mph)
my 05 was the same, 05 blew head gaskets at 25000 mile
06 has 80000 still trying to blow it up, dealer never says a thing about tuner, in fack i took my salesman for a ride with it turned up so he could see how it was intended to run.
the 08 have no power and even worse gas milage

Well going 90 in a diesel will give you crap mileage what do expect lol. Your pushing a brick through the air.

Thanks, I like it alot and it gets attention everywhere it goes, if you want to see it in real life let me know, I live just outside of Apopka, and have a shop in downtown Orlando on OBT.

Well we aren't far from each other at all. Maybe one day we can meet up for a beer or something. My wife used to work at froggers in Apopka, now she moved closer to home to the new one in Mt. Dora.. Though I do go that way to see my sis, she lives over near downtown.

Let me know,,,the truck sits at Nix & Black Automotive on OBT most of the time(unless I'm using it). I probably drive it once a week to keep the batteries up.