" Old flat tappet cams seem to be fine for the most part. It's the newer ones that have issues from what I've seen. Even then it's hit and miss.
I have a 509 MP purpleshaft that's 30 years old and has been in two different blocks. Still runs great.
I have friends that absolutely know what they're doing (not getting into resume's) and have wiped flat tappets on really mild stuff doing everything correctly.

Chip sorry to hear that, what a real PITA !

I've never lost a FT cam before and was extremely anal about the one I just broke in, just rebuilt a mild street 283 for the hot rod.

I had a new (but bought it over 13 yo so older stock) Summit (Crane) generic cam (214/224 and .465" lift) so nothing rad. I used brand new hyd FT Johnson lifters, BUT, every single lifter got refaced to ensure proper radius as I don't trust the manufacturers to do it properly anymore. I also used a proper hi zinc break in oil, I don't play chemist with oil additives and they may not jive with the break in oil's formulation so a always just use a good break in oil with decent zinc and phos. I hope the Amsoil your guy used was their proper mineral break in oil and not the synthetic stuff, synth is a big no no for break in, that could have caused a problem as well. I used old, tired single springs and the same moly lube that I've always used on lifter bases for cam/lifter break in. I also lightly hone the lifter bores to ensure the lifter is free to spin nicely.

I mark every pushrod beneath the rocker to verify that they are spinning when running and use a set of junk VCs with cutouts so I can see if the pushrods are turning during break in. If the pushrod is spinning it means the lifter is turning properly on its lobe. Fired it off last week and all went well, pushrods all turning nicely and changed the oil after cam break in with fresh break in oil and a new filter. I did'nt see anything in the oil filter so hopefully it all went well, guess we'll find out in the next week or two after more driving. Wish me luck.

I won't use a Comp flat tappet cam anymore read way too many horror stories ......imo, if you can find old NOS lifters and older hyd FT cams that suit, snap em up.