Lowering leaf springs

That’s true if the swap is only supposed to be cosmetic. But the SS springs are also super stiff, usually 160 lb/in. If the OP wants to lower the car for better handling the SS springs are too stiff for that, not to mention that they’re not the same rate side to side.

Hotchkis makes 130 lb/in springs for handling, if you leave off their front hangers they will probably drop that car 2” or so from the SS spring height. You can also call Bergman Autocraft. ESPO is a good source as well, although I don’t know if they have anything off the shelf in the 130 lb/in rate. Their 6 leaf springs are basically like factory XHD springs, which were around 110 lb/in.