I bought a set of magnum heads from a guy around here that had those valves with the Hughes hyd roller valve springs installed. More than half the valves were bent and would not come out of the guides. Was run with a Comp cam around .570ish lift if I remember correctly. I dont know what rockers he used tho. I run the Hughes magnum bar 1.65 ratio rockers and my valves are steady as a rock in my EQ heads. I dont have the Hughes valves in mine tho.