Correct me if I'm wrong here but doesn't the super stock spring package also include an extra spring on passenger side to help offset chassis twist under hard acceleration? Good for straight line, not so much for handling.
Yes, the SS springs have an extra leaf on one side to counter the effects of a hard launch so the car launches straight and maintains equal traction.
In a hard cornering situation it would mean that the back end of the car would behave differently turning left vs turning right.
Their arch is too high anyway, and their spring rate is around 160 lb/in. Most of the high end handling leaf springs for these cars are in the 130 lb/in ballpark for spring rate.
The “green brick” used de-arched SS springs, but they used two driver side springs so they’d be the same # of leafs. And I believe they ran without a rear sway bar. Which is ok, but running a softer spring with an adjustable rear sway bar allows for better tuning opportunities.