Without a little more detail from you I am only guessing here. At 598 lift you will be needing a pretty healthy spring. My guess is that your keepers and or retainers are not up to the task. I am thinking you need at the very least a good 10 degree steel retainer with the good forged keepers. If you are turning any kind of rpm I might even consider a titanium retainer again with a good quality keeper.
dkp
dkp