My friend took the broken rocker arm adjustment studs, and had them tested,and found out that they were over hardened, using a test called a Rockwell test. Mopar Performance was pointing fingers at Cummins, and Cummins was pointing fingers back at Mopar Performance, saying that they supplied subpar parts. After seeing the problems with the engines, I determined that they both were at fault. It almost seemed like Mopar Performance was buying blem parts from parts manufacturers! By blem parts,I mean parts that didn't meet the requirements of the manufacturer's specifications, and Cummins assembly work on these engines was subpar at best! Between the over hardened studs,and the improperly hardened camshafts, I truly believe that this was the case.