Upgrading Rims and Wheels for a 1968 Dart GTS

And 15x7. They still make them with 5x4" bolt pattern, and they are available. Also check E-T Mags, ET Wheels by Team III Wheels They'll make you anything you need.
Thank you all for your input this is a great help. The Small Bolt Pattern is always a challenge, but I was considering 15" x 6 in the front as suggested, and then 15" x 7 in the rear with the wider tread in the rear for a little better traction. Thoughts???
GTS Joe