I took the Justice League of America Series 1 Superman, removed the head and sanded down the neck till it was flat with my Dremel. Afterwards. I took a spare double ball joint, and sanded one end into a post, the other into a diamond-shaped nail head. Using milliput and my drill to generate a hole, I created a new neck hole and inserted the post to make a test hole. Once the milliput was dry, I glued the new neck peg into place, and once the glue was dry, added the head from the Smallville Series 2 Clark Kent. Doing it this way, the head retains all of its articulation. Enjoy.