Aerodynamic upgrades?

Hello from Topeka. I thought about this for a bit, and I can't think of anything you could do to change the aerodynamics of your car without changing its looks or costing a lot. A beautiful 67 dart that was physically altered to improve aerodynamics would no longer look like a 67 Dart to me. I can think of two fairly easy things to do. First would be to change your rear tires to something a bit taller if possible. Or switch to a 3.23 rear gear.