I have a F-Superduty 4x4 I’m about to sell…FYI
With its 5.13 gears, 235-85-16, and zf5 it’s spinning ~2850 rpm to go 65mph. Screaming by my standards, but doable. It’ll do interstate well enough at 65 but 60mph state highway is a joy. With 5.13 you can definitely use all 5 gears all the time...