I had two Comp Cams mild hydraulic flat tappets wipe lobes within 20 minutes. I've been doing this for 45 years as a professional so I know what I'm doing. I did everything right and they still wiped lobes, the Summit cam before them had no problems. Comp replaced both of them and I returned the new cams to Summit or Jegs for credit and went roller. No more wiped lobes, but retrofit hydraulic rollers were a whole nother fuster cluck and I bought Morels because they are supposed to be good lifters and they are the same height as the stock magnum lifters. I swapped to magnum heads at the same time. Anyway 3 of the Morels weren't machined properly and wouldn't oil the rockers. Finally got that fixed, after paying for two more pairs of lifters plus overnight shipping, again. They are still noisy though.