2008 Maxforce DT7 code help and cylinder down issue

We got this truck not long ago and already issues. We had cylinder 3 have bent pushrods both intake and exhaust. We replaced the pushrods and did the lash and all was good till about 500 miles later while driving all of a suddun the engine started shaking and feels like it did before. Is this a common problem? or is there a fix so the rockers dont pop off.



No I got the codes
sid 427 FMI 3
sid 420 FMI 1
sid 420 FMI13

SPN 3981 SA33 FMI2
SPN 4026 SA 33 FMI5

 

Is it a clearance issue with the lifters and replace the lifters? Why would you repalce the engine if the same thing can happen there as well?