Thanks Eddie. The 2018 F-150 Order Guide shows that the steepest gear ratio you can get is a 4.10 but that is only available with the 450 HP, 510 LB Ft 3.5L EB HO (Raptor and maybe Lariat). The 3.73's are the best you can get with the 5.0L. But, from what I have seen so far, I don't think that will be a problem.
My '68 Cougar is still in the trailer so when I get a few more miles on the truck I will do a little towing test. It's not the Ike Gauntlet but one of the hills I have to climb to get to my house is way steeper than the Ike but no where near as long. Based on a combination of Google Maps and a topo map of the same area, from the railroad crossing at the bottom to the intersection at the top is 6/10's of a mile and the elevations are 1300 FT above sea level at the bottom and 1700 FT at the top. That's a 400 foot change in elevation in a little over 1/2 mile.
I was never brave enough to try that pulling a fully loaded trailer with the Sport Trac. I always took a longer route with an easier grade. I did do it once with a load of furniture and it wasn't pretty.
The same night I picked up the F-150 I nailed it from about a 20 mph roll on the steepest section of that hill and hit 65 mph in about 2/10's of a mile. My cousin was with me and he said: "A Hemi Dodge won't run with this thing!"
LOL