Almost sacrilege that no one has mentioned Herb Adams' work and why a WS6 handled so much better than your buddy's Z. Look at what he did in Trans Am racing with the Gray Ghost and the Junk Yard Firebird.
https://www.hemmings.com/stories/article/herb-adams
His book will help you understand why. And gives baselines.
https://www.amazon.com/Chassis-Engin.../dp/1557880557