Ihave a 03 2500 dodge 4x4 6 speed, with a vantage 300, and tools in the bed, getting about 18 to 20 with no chip. But building a bed for my 99 F450 CREW CAB fuel mileage goin down hill on that one

rick,,,check this out,,,if your gonna do it,,,do it in a dodge,,,haha, long time no see.  but really get a dodge but not a 6.7,,youll really hate the gas mileage,,,as for the rest of you guys, chips do help,,theyre expensive but they do help.  heres the low down on my rig.  its a single cab black 03 six speed H.O. with a smarty chip, tst powermax on the fly with cooldown timer, 150 gallon per hour fuel pump, industrial injection injection pump, 550hp southbend clutch, ARP head studs, afe stage 2 intake with 6 inch inlet down to 4 inch, straight 4 inch exhaust,, 90hp dynomite diesel injectors,, dual feed line,, and to top it all off an ATS three part manifold with a phat shaft 66 turbo pullin 60 lbs of boost,,and 33 inch tires.  now then my truck also weighed in at the scales at 10,865lbs.  i know cause i got a fat ticket. i do also sled pull with this truck on occasion.  i average 500 to 600 miles a tank on 30 gallons with a calculator,,do the math. and yes that is with a rig.  granted it did cost me a lot of money for all that but i wanted it for other reasons,,,at the time fuel mileage wasnt an issue,,but it sure is a nice bonus