Cherokee 8.25 to 64 Dart?

Normally a 8" wide wheel would run about 3-4" of backspace (4" backspace on a 8" wide rim would be zero offset.) So find a 8" wide rim with 5-5.75" of backspace (or +25 to +44mm offset. That same wheel may not fit on the front though because of the tie rod end unless its 18" diameter. A set of 18's off a modern charger or 300 might be just right, or if you want 15's then longer studs with a 1" spacer in the front should clear.