I need solid recommendations for new valve springs. I have a 440 with a MP Purpleshaft .484 lift cam but I am about to install 1.6 roller rockers. These new 1.6 rockers will put the lift to .516. Based on what I've learned so far I should limit seat pressure to about 120 lbs and open pressure to 300 lbs. I currently have MP 933 springs with a max lift suggesting of .510. I'm sure a spring suitable will be single but with a damper. Suggestions with real world experience needed please. Thanks! Greg