Re-arcing mopar SS leaf springs?

The MOPAR chassis manual states (Larry Shepherd) that cars came with "no" arch under load from the factory.
This was to improve handling in street application.
Yes SS spring may be different. Is the person drag racing?

I have also been SURE that I read somewhere that only T/As and AARs came with camber in the springs. But did not know where I read that.
I stumbled on it recently while cleaning out.
It is in a "Service Builtin".
I believe this was for the exhaust to clear.
I can document both of these now.

I say this to help.
I bought a new pair of MP springs for a Challenger (not SS) because I thought the springs were sagging.
There was no difference.
Still Flat. Wasted money.
I have added springs to my car to make the rear stiffer due to it being an M body rear under an A body and the tires hit on bumps.
I did not raise much if at all.
And Larry Shepherd also states that when the rear of a car is made stiffer it tends to increase oversteer.
Be aware.