I recently got new 6" front springs so I pulled my old 4" springs off. About 2 years ago and probably only 500 miles ago I added a block similar to the zero rate center bolted block up front. I had mine made with a bit of a taper to them - can't remember the exact amount but it was what is typically used with about a 6" lift. When I pulled the center pin to remove the tapered block I found that the head of driver side center pin was bent slightly. Who knows if it would have ended up breaking. I'm glad I'm back to having no center pinned block up front and just wanted to give a heads up on my finding.