I don't know what model you have but I've got a huge arm rest in the middle and more cupholders than I know what to do with...

 

just got back in town. what the dealer sold me was Ford power stroke cetane booster and performance improver. 4oz per tank is what they said.. label says ULSD compliant

 

Fuel mileage: 190.83 gallons for 1665 miles all towing 16,650# gross is 25,350# with my F450 4.30's, the computer showed 9.1 and hand calculated 8.73. Usually drove up to 5 mph over the speed limit under 60 and tried not to exceed much over 65, except in W. VA where it was 70 mph and kept it lower than the speed limit on some really rough roads and bridges. It also surprised me coming off traffic lights in heavy traffic, ¾ throttle had to look behind me to be sure the camper was still there (well almost) it really pulled strong and had no problem staying with traffic between lights. If you want fuel mileage go with a 250 standard cab with 3.73’s, If you are going to tow heavy go with either the 350 4.10s, 4.30s if heavy or a 450. From what I have experienced the 4.30’s will have no problem even over 20,000# towing. I wouldn’t think you would need 4.88’s unless you are towing 22,000# plus. further info on another 6.4 post