For the front, you will need '70 fenders (to properly locate the headlights in the grille - the fenders are not the same), '70 fender side markers, '70 grille and removal of the '74 front header. You will also need '70 bumper brackets to suck the bumper in closer and a '70 bumper to be absolutely correct.
For the rear, removal of the '74 tail panel, '70 tail panel, '70 taillights, lenses and bezels and (I believe) to modify the taillight wiring harness.. Figure $4000+ in parts alone. Same situation with the bumper brackets and bumper.
Mike