The move down and forward in instant center is really the claim to fame for Caltracs. And it's adjustable via the front link positioning, and preload. Without going to some real expensive stuff, it's a hell of a "bang for the buck" bolt on.

 

were the ones that you got from Mustangs plus assembled with poly bushings of rubber

 

shelby under riders are not adjustable.

bushing?...must have been rubber cause I don't even remember seeing it