Its hard to say as the butt dyno and how its applied to handling can be very subjective calls. Its even possible that cars can be mechanically capable of each other but one simply feels better because of geometry, alignment, seating, or any of a myriad of differences.
When I played in the GM world, street performance spring rates were around 400#, which is around 200# in the torsion bar world. Classic Mopars can easily get to that point. Then it becomes controlling the motion (shocks) and improving the geometry where ever possible. Mopars overall have better geometry than many of their contemporaries, but the shared cast/camber of the upper arm eccentrics become limits pretty quickly when chasing down really good alignment numbers.
and that’s why he needs to go ahead and run adjustable upper UCA,s. I’m thinking I got twice the amount of adjustment out of my SPC,s then my old offset moog bushings. Can’t remember the numbers but when I get it put back together again I’ll have the alignment guy to write it down.
