I talked to comp cams as that is who the mopar performance tech guy said manufactures the purple cams now for mopar. Mine is old enough it was probably made by racer brown. Anyway they seemed to think 350 psi seat pressure would be good for the rpm I wanted . Aka 6500. The springs I have spec at 318 psi at 1.3. I am compressing them to 1.2 Ish . I would imagine they would be in 350 to 360 range. I may grab one and take down to a machine shop to see what it measures at that height.