New to site w/a lot of questions

:welcome: to the fray!!
I like the rear bumper of the '71, will it go on the '73? yes - if they are both Scamps they should be damn near identical. (are you sure the 73 isn't a 74??) Can the front of the '73 be fit with like the hood/grill of a 71-72 Dart? no - it requires a full nose change... though the fenders can stay.

with that said - nothing is impossible if you want it badly enough. :thumbsup: Darts and Scamps are essentially the same car..