Yes. If you don't firm up the chassis, then the body of the car becomes an active, albeit an inconsistent, part of the suspension equation. The chassis is the foundation all mods are based on. Make it a good, solid one and it will allow the suspension to work better.
I ws stunned at just how much firmer and more positive my 100% rust-free virgin metal 4dr Dart felt, with its stockish suspension, than my rusty 72 Charger, with its upgraded suspension and better tires. I used to notice the same thing waaaaaay back in my youth driving a friend's Nova compared to the Buick A-body's i used to drive.
I couldn't imagine how wicked a stiffened up E-body with all the chassis mods would be. Come this summer... i wont have to. My 74 is getting all the mods. I might even weld up all the seams.
