73 duster 17" or 18" wheels ?

Late model Charger, Magnum, and 300C wheels fit as well.

I am in the same boat as you are. I have a 74 Duster in need of modern wheels/tires.

There are a number of choices for us.
What needs to be done, so that YOU can maximize your effort, is:

Measure YOUR Dusters Differential In Relation to YOUR Dusters Chassis/Leaf Springs/Wheel Tub.
Here is a great tutorial:
https://www.rsracing.com/tech-wheel.html

It seems everybodys car is different, and setup differently....and this question comes up all the time and the answer for one is not always the answer for all.

Here is a good thread about what fits A-body's from Moparts:
http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Board=QuestionAnswer&Number=6083482

A 275 series tire for the rear is pushing clearance without the leafsprings being relocated....and wont fit without careful measurement.

255 series tires are an option and usually wont fit without special wheels/spacers.

Most people opt for a 245/45/17 or even a 235 45/17 because of this.

Most aftermarket rims locally available like at discount tire, tire rack, or sears auto service, are the normal sizes and offsets....mostly 17x7's.

On the front your concerns are theDisc Brake Hub register, Upper Control Arm Ball Joint, the outer tie rod and the fender lip....Some of the new wheels have a smaller hub center hole and will not allow the wheel to seat down flat to the hub without modifications or spacers.

Do you have any styles/sizes you are leaning towards now, so we can critique them?

I really like alot of styles of rims here:
http://www.coyswheel.com/
But I really Love the way Gdemon's 6.1L Hemi Demon looks sitting on these late model 300C steel wheels painted to look like Rallys

wow, that looks great! Those are stock 300C rims??? 17 or 18's? Damn, I must have been asleep at the wheel...