Old vrs New - Performance Questions

[FB Coach]

Here is what I have done.

Old Truck.- 01 Screw 5.4, 3:55 running 265’s with a K@N FIPK and a Magnaflow si/so.
Has been passed down to my 16 yr son who just started driving. Very lucky boy. This truck did have the larger upgraded radiator that ford was putting in the trucks but has since stopped that practice.

New Truck – 08 Screw 5.4, 3:73 running 285”s. So far no mods except a 2 inch body lift. In the future a Gryphon Tuner ,Magnaflow exhaust, drop in K@N filter.

I tow a trailer 2-3 times a year from sea level up to the mountains 8,000ft.. It weights about 6,000lbs loaded. The old truck would slow down pretty good on the hard pulls, but seemed to handle the weight fairly well. Tranny temp never went over 215 even pulling Sherwin Summit in 105 degree temp. (6-7% grade for about 15 miles). How do you guys think the new truck will do compared to the old truck? My concern is the cooling issues and the larger tires. After I do the mods I think it will have more towing power than the old truck but I am concerned about how it will cool. I know I could put a different tranny cooler on it, but I am concerned about warranty issues.

Any suggestions or opinion out there.