A valve train assembly having a valve train carrier including a body having a cartridge cavity formed in the body, a hydraulic lash adjuster adjustment (HLA) assembly, and a cartridge removably disposed in the cartridge cavity. The cartridge includes a main body defining an inner bore, wherein the HLA assembly is disposed in the inner bore, and the cartridge is sized and shaped for insertion into the cartridge cavity formed in an underside of the valve train carrier. The cartridge is configured to have a valve train lash set prior to insertion into the cartridge cavity. A rocker arm assembly includes a body configured to engage the hydraulic lash adjustment (HLA) assembly, an end having a socket formed therein, and an e-foot extending through the socket and coupled to the end, the e-foot configured to maintain substantially flat contact with a top surface of an engine valve.

A deactivating hydraulic lash adjustment (HLA) assembly includes an outer body configured to be received within a cartridge for a valve train carrier, a plunger disposed at least partially within the outer body, the plunger including a hollowed inner area, and an inner body disposed at least partially within the outer body and at least partially within the hollowed inner area. The inner body includes a low pressure chamber defined therein, and a high pressure chamber is defined between the plunger and the inner body within the hollowed inner area. The plunger is movable relative to the outer body and the inner body.