I pulled my 31.5 ft which was 4,950 lbs dry home with a 3:31, 5.4 equipped Expedition. Let me tell ya, it was miserable.
I bought a F150 super cab with the 5.4 and 3:55 gears and it towed much better. Imho opinion based on experience, dump those 3:31 gears and step up to 4:10.... that’s what I wished I had done.
One thing, make sure you have a transmission cooler...you will fry the transmission without it.
There is a small cooler on the drivers side in front if the radiator. Don’t mistake this for the Transmission cooler. It’s the power steering cooler.
BTW.. they are not small full sized trucks. It was the first body style of the sloped front end. But that trucks dry Weight is just a little less than my current SCREW.
Thanks!
Jeremiah