I had a 99 5.4 EB that I moved my folks from NY to CO with.....and several other foolish overloaded tows. It WILL do it every time, but you will feel like you are hurting the truck. These triton motors love to rev however.
I had a 5.4 box van with the five speed auto. I would do another 5.4 as long as it had the 5 speed auto. That truck always seemed to be in the right gear and would pull more than it should.
The v10 is so thirsty, that unless this is a dedicated tow rig, I'd do a 5.4 and deal with sluggishness during occasional trips towing.
The 7.3 diesel is the best, but it seems owners of them are proud and I personally won't own the 6.0
The Chevy 6.0 would be my choice:coffeedrink: