I've never in my over 50 years of messing with flat tappet cams started up a SBC or BBC and not done a 20 minute cam/lifter breakin at around 2500 rpm's. And I've also never lost a cam in any new cam install. But the last flat tappet I did was close to a decade ago, and even then cam failures were fairly common with flat tappets.
Back when all this started it was commonly stated in numerous magazines, and with engine builders, that it was the oil. The lack of zinc was blamed for the failures, so that last SBC I did then got Brad Penn break in oil as recommended by the engine builder who did all the machine work. I broke it in with the straight 30w Brad Penn oil, and then changed out at 500 miles like I always do. Cut the filter open, and checked the oil to see if I saw any sparkles indicating metallic particles, and all was fine. That engine has 14,000 miles of street/strip use, and a lot of full throttle runs down the strip also. I only run Valvoline VR-1 since, and it also has high zinc.
I can't say if it's only the oil, as I've had others tell me they did everything right, and still had flat tappet cam failures. But my personal belief is if you buy quality cams and lifters, and use the right high zinc oil, and break it in, it ought to be OK. But I wont chance it myself again, even though it worked for my engine.
My current engine is a 1990, so it uses a factory roller lifter, which made the lifters cheaper. Howards roller lifters were $265, and the cam was $257. So not much over $500 total. Retrofit are quite a bit more, and I don't understand why since it's really just the links that are extra cost to the cam makers, and they sell far more retrofit cam kits than kits for factory roller motors from what I've been told. I could understand an extra $50-$100 for retrofit, but not the 2x price they seem to be asking.
