The front suspendsion on our vettes was taken from the 58-64 chev full size cars, some parts interchange, including the power sterring, impala, bel-air, I don't remember ever seeing progressive wound springs on those cars or any C-3's, your springs might be aftermarket, heated, or saging springs, if you replace the fronts and you still have the original buggy spring rear you might want to consider replacing it to with a fiberglass one, if you have a glass rear already take the # off of it so you get fronts to match the rear, I believe there are three rear spring rates, you want the fronts to complament the rear for a balanced suspension. anips2009-08-12 12:23:00