sagging rearend? A buddy of mine hs 65 coronet 4dr. w saggy rear. I remembered long ago that NAPA used to carry,"leaf spring helpers",consisting of 1 half spring for each side,and a bolt on kit. Well my friend check the same NAPA store 30 years later and they still had them !! Bolted them up and car sits 3 inches higher than it used to... As for how long it last??Only time will tell !!