You will definitely need to adjust. Rule of thumb is that you need to be within +/- 1 inch of being level. If you are currently level with the Expy, you already know that you will be at least 1.5" high with the F250.
Plus, since the F250 has a much stiffer rear suspension, it will not squat as much. I would not doubt you will be 2.5" tongue-high with the current setup.
WDH shank typically has a universal hole spacing of 1.25". So you should try dropping the head 2 hole-spaces. Hopefully, you have enough room on the shank for that. Otherwise, you'll need to get a shank with more drop.
thebrakeman ('70), DW ('71), DD ('99), DD ('01), DD ('05)
2004 Surveyor SV261T (UltraLite Bunkhouse Hybrid)
2006 Mercury Mountaineer V8 AWD Premier
Equal-i-zer WDH (10k), Prodigy Brake Controller