The 6.6L LML Duramax cylinder heads, used from 2011 to 2016, are made from cast aluminum for strength and better heat dissipation. They feature a four-valve-per-cylinder layout, improving airflow and combustion efficiency. Compared to earlier Duramax heads, the LML versions have revised cooling passages to better manage heat under heavy loads. They are designed to work with Bosch high-pressure fuel injectors and integrate with emissions systems like EGR and SCR. Hardened valve seats and improved port designs help them handle the increased demands of modern diesel performance and emissions standards.