I have a F250 6.0 and have just under 250k on her. The truck before that was a 2000 F150 manual transmition with the 4.6 v8 and I got 334k on it before she died. That's when I made the move and went with the diesel. the repairs are starting to add up with the 6.0 so I am looking to upgrade to a new F350 6.7. I do a lot of driving so thats why i think the 3.31's will be a little easier on the fuel bill.