A solid lifter cam is only as good as....

1. The engine its fitted to. If the engine has poor oil pressure, it's going to cause problems.

2. The person thats fitted it. The clearances are SO critical. Hydraulics are easy, just bang them in, but Solids are entirely different.

If the clearances are allowed to be wrong either from poor setting up or a bit of initial wear, then the problem will soon arise. It's exponential, the greater the discrepancy in the clearance, the faster it will self-destruct.

Newman isn't the absolute answer, but I say again, it's the best of whats available.