So, if you were switching gears from a 3.73 in an Excursion with the V-10, would you go right to 4.56 or 4.30? Gas mileage is not a concern, and it's in a 2WD.
4.30's with that gasser will give it great towing ability. Towing mileage should be the same or better than the 3.73 ratio, but unloaded mileage may suffer a little.