THIS is what we have experienced We have had 7.3's 6.0's and now a 6.7 Cummins,, the 7.3 very reliable,, 6.0 yes problem I have had 2 and now the 6.7 Cummins,, all 4 trucks have pulled very heavy weights up I-15 out of calif up to Las Vegas, Nevada, up in the hills of Oregon/Wash across the I-40 in Az or up I-17 corridor,, these weights exceed 30,000 lbs with just the last trip 2 weeks ago at 37,855 lbs and what we have said all around that a 6.0 stock air cleanor 4" exhaust will out pull any 7.3 with equal weight and wind drag and by wind drag stand up 2 8' beds on back of a truck andsee waht that does and like I said our 6.0 with that set up went up against all of those broke down Chevys and Dodges but a far as reliablity forget the 6.0,, our average for fuel for every 1/4 was 9.4 with pulling 2 different trailes and our 1 trailer enclosed is a extra 1 1/2 higher than most,, our 6.7 cummins last 1/4 was 9.2 but look at the size F-650 Crew Cab Roll back,, I know when back in 2004 when I got our first 6.0 like wow and even running across Texas told one person if you want to run with this 6.0 better go to Ford and get one

but that me,, the 6.7 Cummins has less power but heck look at the warranties Ford Could not even match Unlimited on Trans for 3 years and 2 years unlimited on Motor then afteryears up can be updated on the basis of mileage on vehicle Just our
