[AnotherWs6]

So are you saying that the passenger side is pushed forward in the wheel well? That's what it looks like in the pic.

I'm a noob to these older trucks, but this happened twice to me on my 99 Silverado. The bolt that goes through the leaf spring pack sticks out on top. When you tighten the u-bolts that little head has to be positioned in a little hole in the upper bracket in order to keep the axle and u-bolt from walking up the springs and causing what you seem to have. Long story short that bolt has broken twice on me and I knew both times because one wheel would be wy out of whack in the wheel well.

So what keeps the wheel from walking on these things? You added blocks to it, my bet is that something is wrong there.

And yes, one side of the axle can move while the other stays in place. A lot.