Not wanting to throw a monkey wrench into your plans, BUT it really depends on how exact you want to make it a true 71. It's not just fenders, hood, grille, headlights, emblems, and taillights. The 70 is a 1-year car in a lot of respects, too many to list here, but some examples are steering columns, door locks, front seats, dash pad, shifter (if auto), console (if equipped), etc. as well as the obvious front end sheet metal and trim, wiring, taillights, etc. There are tons of small detail things that are different between a 70 and a 71. If you want a correct 71, then start with a 71. If you just care about the overall look of it and not the details, then either a 70 or a 71 will work. It just depends on how much detail you want to get into. There are dozens if not hundreds of small differences between the 2 years. In some ways, the 71 is more closely related to the 72-74s than the 70, but because of the taillight openings people think they are similar.