The blocks add a ton of leverage against the spring making axle wrap worse. Imagine a 15" block and how easy it would be to bend the springs, so yeah, even a 4" block makes things worse. I'm sure getting rid of them will help. Make sure to keep the overload leaf too. It will limit upward flex like a bumpstop and help when the truck is loaded. It's tough walking the line between something you haul with and something you wanna have fun in. I would only do 64s for flex, but you are looking at them for rid quality. Right now, my truck rides really smooth 52/56s but I have very little payload-ablility.