Home made spring shackles

Hi guys, I'm new to the site. I have a 66 Barracuda that sags in the rear, probably due to aged leaf springs. If I were to fab up a set of spring shackles out of 1/4 inch bar stock to gain 1-1/2 inches of rear lift, would that work o.k. or would they have to be hardened or made from thicker stock? I know, I know, it's the cheapskate's attempt to avoid spending the money on new springs!!!:toothy10: