Value of '71 Duster 340 Basketcase
Sum of the parts is great for your car, as a complete package, not so good, IMHO. The max I'd pay for a car like yours would be 2K.
The parts are definitely worth twice that amount
It's a tough decision to make, however, basket cars don't get top dollar unless they are E-body hemi verts.
Reality on this really sucks sometimes. You could always E-bay it and see where it goes.