Proportionately wheel size depends on the car.
I think A bodies look fine with 15" and even some 16" wheels.
B's looking good with 15's, 16's, and some 17" wheels (on station wagons).
C bodies, especially station wagons, can easily make a 17" of even an 18" wheel look good, as long as it's tastefully done.
I also think that Ram trucks with 20's (factory available) look great.
Saying that this size or that size is out of the question is being pretty closed minded. It really depends on the application.
On my 71 Dart I used to run 13 x 4.5" in the front and 15 x 7.5" on the back, back in the day, and it looked great. It sat pretty high, too, and had a "gasser" look. Today it would look rather silly on the street, not to mention that handling sucked. lol
Today it has 15" Torque Thrust D's all around. They fit the car wonderfully, and they augment it's era.
