As far as I can remember you need to change the header panel, front valance, the part that holds the headlights in place(can't remember the name), either fenders with gills or gill patches, bumper brackets, and the grille. There are also little things like the electrical wiring for the lights in the valance and the four headlights, but that can be done with a little wire and some connectors.
I'm changing my 72 into a 71 so I've been picking up all the 71 specific stuff for my car.
If I can think of anything else I'll add it to the list.