4WDH list front leaf springs 1941-53 and then 55-75 seperate while JC whitney list 45-71.. is there a differance in these springs other than 8 and 10 leaf?

I ask becuase I need a set of front leafs to fit my chevette, I have 1 3/4 inch wide 8 leaf sets. and I dont want to buy the wrong part if there is a differance.