.......Back to your buddy's wheel hoop / tire chatter issue....
Tire shake is a function of the suspension moving with more force than the shocks are adjusted to "dampen". To make an adjustment, stiffin the rebound first, then stiffin the compression to help hold down the tire once it gets applied. The goal is to match the dampning values with the level of force/energy passing thru the shocks. Consider selecting shocks that are designed for higher horsepower applications...like the AFCO BG-Big Gun series Shocks.
When setting ride height, start with the shock shaft 1/2 way in/out. Fine tune from there. Be sure to guard against shocks bottoming out. If the installed height of the shock is to short, and the piston (on the end of the shock shaft) hits the base valve (at the bottom of the shock), and damage will result.
When choosing rear springs, it is suggested to err to the softer option. A softer spring rate will typically be more consistant over the range of starting line conditions.
Run that by ol' Pete...and see if he agrees...no charge!
I might be a little nutzzzz,.... but I'm just not another pretty face)
