My thoughts to kill 2 birds with 1 stone......maybe 3.....
You said you need new tires, buy 255/85-16 (33”)
Option 1: Find 3.54 axles, rebuild and swap, pull a leaf or 2 out of the rear and maybe lighter duty coils for the front (possible?) to get your F-150 ride and rev drop.
Option 2: E4OD with standalone controller. Program for your liking. 33” tires and .71 @ 75mph is around 2250rpm. Then work on your F-150 ride.
Your already this deep, go find the bottom!! Wouldn’t your gasser be full of sensors or were you thinking carb? And do you drive your F250 much in the winter since it’s so nice?
I vote option 2 and 66% of my vehicles are standards.