Main part 4083569 engine connecting rod with cross-reference 3899450, 3896970 applies to Cummins QSM11, ISM11, M11, L10 and X15 engines. Precision forged metallurgy withstands huge reciprocating impact force generated by combustion events. Every key mounting hole is machined to tight tolerance standards. It restores engine mechanical performance in major bottom?end rebuild projects.