Every cam I have seen do this was due to lack of lube due to lack of oil changes or the backyarder mixing old used lifters after installing the legendary full race cam . I'm with Mike and have never had one of mine fail . Good oil , paying attention to the details upon assembly and break in or a combination of both ?

Ones I've seen were in good running engines with regular maintenance. I can only speculate that it was a bad core? Speaking to the lack of lube or maintenance and how it would affect a flat tappet cam, I can relate a personal story on a '79 Malibu I purchased in '85 as a college car. I knew the car had not been well maintained mechanically as the original owner was too cheap to replace a ripped wiper blade and the passenger side of the windshield was scored pretty bad. The price was right and the engine didn't smoke and checked out OK so I brought it home. The rotted out freeze plugs and the mess I found under the valve covers really spoke to just how poorly the car was maintained. Not shatting you I had to take a flat blade screwdriver and scrape/chisel "coked" junks of oil out from around all the valve springs, rockers, etc. How this engine was able to drain oil back down to the pan was beyond me. So, between running with oil that probably hadn't been changed in years and me then taking a stiff brush and kerosene and washing all around the springs and rockers with the heads still on the motor and then giving the motor a couple kerosene "flushes" you would think that would wipe the cam/lifters out. Nope. Ran like a top for the next 2 years and over 20K more miles. The engine was Chevy's flagship 267 cu in V-8 with a DuoJet. Flame thrower!!

Boy, those were some dark days in the world of automotive high performance, weren't they? I think that was close to the time that the T/A was about the hottest car you could buy, and even it was reduced to the crappy turbo 301 at some point. I really thought the high performance game was dead and buried at the time. Who could have guessed that 30 years later you could walk into a dealership and buy a 400+ HP fuel injected machine with a 6-speed manual?