Most missed the point..............and that is, there is NOTHING special about SS springs that you can't do yourself. Need more rate or a stiffer segment? Add some leafs or half leafs. Like the short front segment? Use A-body springs. Any spring pack can be made to work just as well as any store bought SS spring pack. Spring steel is spring steel. Only two things come into play. The arch on the spring and the number of leafs or half leafs.

Been many a spring pack that wasn't a thing wrong with, thrown out behind a shop, because someone was told they needed the magic SS spring to make their car work. When all they probably needed was some clamps and maybe a leaf added