It will be interesting to see how much flex is gained by removing my son's overload leaves from his stock-length rear springs. Near as we can tell, they are first-generation Alcans. The only downside in removing the overloads, is if he overloads. We have a short leaf we removed to take them from 4" to 3", we could just remove the overload and replace the short leaf and that might work out. He might pick up a BUNCH of flex even with the stock-length springs.

Oh, yeah, we used stock shackles too, to keep the lift down. This is also a consideration on flex.