The 340 is out....again.....

Well it could be they never changed the cam bearings, old bearings that sit and go through hot, cold, moisture condensation etc...those literally fall apart and especially so when the driving style or load increases.
Corrosion. Could also be they had the cam in and it was WAY tight , needed bearings cut or polished and they said ehh instead and just threw a chain on it...or even better, they clocked the bearings wrong and they just burnt up and hurt the rockers in the process. Like you said, doesn't matter now, I'm just curious and it Kay save others from spending money at that particular business.
What did the bearings look like?