It's possible, but you will need the intake manifold and all of the rest of the induction pieces. Plus a new tune to compensate for all of the changes. It might be easier to swap out the entire motor.
You can swap out 2v heads for a 4V head, but it is not feasible cost wise. Here is a list you will need at a minimum for the swap to even work right.
4V Throttle Body
4V intake
4V heads and cams with secondary chains/covers
4V crank being now the engine regularly revs to 6800
4V pistons being the CR is now different with the heads
4V flywheel to match the crank
24 lb/hr injectors
modify the harness
tune
I know there are other things needed, but this is the main list. You are better off getting an entire 4V motor as it will be cheaper