I also had a bunch of lifter failures comp lifters were not up to the task of a spring that's 1290 over the nose of the cam, super charged would have the same affect. I went to full body lifters/keyways and that problem was solved
When I was building my engine, the Competition Eliminator racer I was working with at the time talked me into running the keyed lifters. He said that that the tie bars introduced an harmonic that could cause problems.
Maybe you are seeing an extreme case of this phenomenon.
