Thanks for all the replies. I wasn't worried about stressing my drive train as it is the same as the diesel. But I have decided not to do it. Rousch no longer makes the 590 horse for the Super Duty. The other choice is a Whipple with 675 horse. Even I think that would be too much stress on my engine hauling heavy, compared to a Mustang anyway.
When I'm done with the off road thing I may trade for a diesel and a Toy Hauler. But I can not stand campgrounds (screaming' kids, barking dogs, loud music and drunks). So when I'm done with this rig I just may be done for good!!