Need help from the suspension gurus here!

So Menscer wanted you to go stiffer than 250? They just want the spring to hold the car up to ride height with no energy in it. Yeah, there is a 9.4’s second ZL1 Camaro running in the class that has a good 500-600 hp on me and about the same nose weight. He’s running a stiff front spring, he doesn’t need any help getting it to transfer and the rate of transfer is within his shock tuning window. Each car is so individual.

what size and kind of rear tire is he running _??