Mancini extra heavy duty springs sagging

I just installed the new leafs in my 1970 swinger and now its sagging. Are LH/RH specific? Im pretty sure they had the same part # on them(1982), they look identical. Now they are in the car and I can only see one of the part #s. I have the one that I can find the # on in the passenger side. It is 1.75-2" low on the drivers side. Finally got my 8.75 in (3.90 suregrip).. 383ci 727(2800 stall(soon))