I've been looking at GM gas 3/4 tons and ran across a few F250s with the 6.8. What kind of fuel mileage does the 6.8 get and did it have the problem blowing spark plugs that the 5.4 had?
My 02 X gets 14 hwy not towing and 7.5 towing. Not great numbers, but my 32' TT weighs 9200lbs and is 11.5' tall! The early V-10's had the plug issue. That was fixed late 2001. The newer 3 valves have some of their own issues. Like timing chain tensioner issues and spark plug removal problems due to the design of the cylinder head!