I have had troubles with my .541/.537 lift roller cam in my 440...I am using 440 Sources Stealth heads with new 10 degree locks and retainers...the only info they give for the springs is that they are good for up to .600 lift cams.....wtf....I believe their springs are too strong for the roller lifters and are overcomming the hydraulic plunger when the lifter pushes the valve open.....I am going to buy the recommended 925-16 springs from Comp Cams...my real question is has anyone put dual springs on their heads and is there any machining required? I am also running their 1.6 ratio rocker arms and final valve lift is around .578....​