No, it can be done with the head on.
It's really not that tough... you'll need to pull some IC piping, some heat shield(s?), the vertical coolant hose off the top / back of the block, and then use a BIG socket to pull the fitting off. A long set of needlenose pliers works wonders on the other end of the hose.
After you get it off, replace with virtually any molded elbow with the same size inner diameter, and cut it to match in length.