2006 – 2007 6.6L Duramax LBZ

The 6.6L Duramax LBZ was a short-lived engine only available for two model years. To meet increasingly strict emissions standards, the LBZ was a more aggressively tuned version of the previous LLY engine.
Mechanically, the LBZ used the same parts as the LLY, but the LBZ generated 360 horsepower, while the LLY only generated 310 horsepower. Torque increased as well, going from 605 pound-feet with the LLY to 650 with the LBZ.