First off, WELCOME to the Stovebolt
Awesome site wit awesome people and trucks
Well, it CAN be done but you will need a 4x4 truck for all the pieces and parts to swap to your frame.(Cross-members for engine and trans, spring-hangers and springs, 4x4 front axle etc.)
I personally feel that it will be much easier and less labor involved to swap the 2x4 body onto the 4x4 frame.