Very possible. You'd need the complete engine with the engine harness, PCM, Y-pipe w/cats, radiator hoses, complete transmission, clutch if it's a manual. Probably also need the throttle cable and cruise cable if equipped. Save yourself some grief and get it all from the same 2000 donor. You'd need to have a Ford dealer "introduce" the 4.0 PCM to your truck's PATS Module unless you also transfer the PATS Module over from the same donor.
2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals
BW4406 manual transfer case, Aussie Locker, Torsen L/S, 4.10's
Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, ABS switch, sway bar discos
Heated seats, Explorer EATC, Trip Computer and consoles
2003 XLT 2.3L M5OD-R1 reg cab beater, 2011 Taurus SEL, 2016 C-MAX Energi Plug-in Hybrid