Well sorry about your bad Ford 6.4 diesel experience. As Lantley posted that gasser will get the job done, but not like the 6.4 did. When they are running correctly they are a great engine, just has issues.
Dropping the rear ratio will help, not sure of the trade offs. It will never pull a hill like your 6.4 and for their really bad fuel mileage the 6.4 got, likely better than that 6.2 both pulling and non pulling.
Well the choice is yours, drop in the new gears, get a little better towing, and worst mileage, or stick with what you have and just deal with the higher revs to get up the hills.
