I wanted to post an update on this. Recap: I installed brand new leaf springs from St. Louis Springs on the front of my truck. When I was done, the passenger side was about an inch and a half higher than the drivers side. Both springs had blocks under them that were about 5/8 of an inch thick, so I removed the one from the passenger side. Truck is much better but still about 3/4 inch uneven. Also, I discovered that in addition to the blocks, each side had one caster shim, which I assume has to stay. When I look at the two springs from under the truck, the passenger side has much more of an arch to it than the drivers. The drivers side spring is flatter. I didn't notice any difference between the two springs when I got them but I'm wondering if they didn't send me two differently arched springs. This problem didn't exist with the old springs. So tomorrow, I get to pull both the new springs and compare them side by side to see what the heck is going on. If they're the same, I'll swap them side to side and see if that makes any difference. I doubt the spare tire mounted on the drivers side is causing this, since there wasn't any problem with the old springs. If anyone has any experience with this, I'd appreciate hearing from you.