Camaro rear spring problem

[68CamSS]

68 Camaro SS multi leaf- Has anyone ever had trouble with the leaf springs being so stiff that there is hardly any travel in the rear suspension? Purchased from HBC, they're the ones from Eaton still being made in Detroit. Is there a correct or wrong sequence for installation? Was there something done wrong that would "preload" the springs. Back end hits like a truck, no give. Shocks are good. Thanks for any help

[njsteve]

Did you wait til the car was sitting down on the ground before you tightened the shackles and the front eye bolts to spec? If you don't do that the bushings get preloaded in the wrong position and are trying to twist themselves when they can't move.