It has been done. If you want it completely like a 70 then the tail light panel will have to be swapped out, the reflector lenses on the 1/4s and fenders will have to be changed to the 70-71 style, you will basically need a whole 70 front end, you will need 70 bumpers, and on top of that you will have to do the interior too. However, if you just want it to look like a 70 while ignoring the little things, then you will only need to switch the tail panel and front grille, which is still quite challenging.....