It is possible. You'd need everything froom a 4.0 donor truck that touches the engine. Trans, exhaust, wiring harness, ECU, etc.
If you're going to swap it all out, I'd swap in a 5.0 instead of a 4.0. It's almost the same amount of work, you get a better engine from the start, and there's a much larger aftermarket for performance goodies.
There are some options for performance stuff for a 3.0, but most are not cheap. Very few people choose to add performance to their 3.0, so there's not a lot of info or credible knowledge out there. The performance gains just depend how much skill you have with engine mods, how deep your pockets are, and what your power goals are. If you're serious about 3.0 performance, I'll post some links for you.