Recommendations steering box 70 Dart

Sway bars and SS springs don't work together.
Sounds like you want something for the canyons, with the fat sway bars, tubular control arms,etc. If that's the case you would be better off with a set standard replacement springs.
SS springs are for 1/4 mile jaunts.

What is it you want your car to do ?
Street Strip Canyons Groceries ?