I replaced the front springs on my 61 3/4 ton 4x4 because they had a pretty good negative arch. Mutual Wheel co. had a pair in stock that were real dusty. Probably been against the wall for decades. The new ones looked real good in the bed of the truck but when I put them on, they went right into the same negative arch. I gained nothing but i learned a lesson about those front springs the hard way.