I'm not a 4 link expert and I'm sure someone with greater knowledge than I can chime in.I was told that it helps in traction with my ls-1 set up and also since the truck is lowered it keeps the pinion angle in tact, allowing the frame to "float' while keeping the drive angle constant. In my case the complete spring set up was in need of replacing or go with the 4 link. The 4 link was a couple hundred more than the complete spring / leaf set up. the 4 link has built in adjustments that allows 2 inch of adjustments up or down without blocks.
