R&P for A-bodies

There's a company named "Gerst" that has a kit for about $3,500 bucks that seems kinda reasonable but I'm thinking if the early P/S cars like S&M, Landy, etc. found a way someone knows something that'll work. Can someone explain to me just why , because some bars are attached to the LCAs that someone can't get the geometry right? I have no problem with coilovers but just how can I keep the LCAs in the car?