By the time the LBZ came along, the LB7’s injector issues had long been solved and the overheating issues associated with the LLY were a thing of the past. This engine’s beefier block casting, stronger connecting rods, higher pressure common-rail fuel system and updated ECM arguably made it the most powerful, drivable, reliable and tunable Duramax to date. Right out of the box, the LBZ produced 360hp and 650 lb-ft of torque. During this time frame (’06-‘07), these numbers not only outperformed the 6.0L Power Stroke’s 325hp and 570 lb-ft, but they beat out the 325hp and 610 lb-ft figures put up by the 5.9L Cummins as well. The LBZ was also the first Duramax to be coupled to the six-speed Allison 1000 automatic, which proved capable of handling more power than the five-speed version that preceded it.