comp lifter failure
I havent gotten a Comp Cam sinch last year, but the last one I had did not use that clip style, but a wire retaining clip. Edelbrock uses that spring steel style and they are junk. I've found them hanging on the pushords because they pop out. 6 of 16 on the last RPM cam equipped engine I took apart. I don't think they are the anti pump ups. I think those are the standard hydraulic lifter.
63- On most performance lifters (the anti pump up, and variable duration) you need to have much less preload... instead of .030-.040, they take .010. You must have the adjustable valve train to run them. Look in the catalogs and there is a footnote for that.