i did it to my 72 and its not to bad ,,just takes a little time and work,,of course i dont care about resell value and i really dont think it lowers the value as alot of people like the look of the 70 better and would pay more for that instead of buying a real 70 that will always be a higher in value anyways,,unless its somebody wants numbers matching,,but that doesnt matter if you dont have the numbers matching motor an tranny,,that would have been the only reason not to do it ,,and if you just do the grill only its not to hard to swap back to the original,,the marker lights would be hard to put back,,the rear panel would have to be cut out to put back but if you save the old one it can be done,,of course on my 72 the bumpers didnt have to be changed,nor did the mounting brackets,the hood latch is different but not the safety latch,,you will need the 70 style hood moulding