01-early 04= LB7 , 300HP, 520 FT. LB. torque. 01&02 model years had injector problems, but have a 200,000mile warrenty on them. The 03's have the warrenty now as well too! The 04's have redesigned injector and have very few problems, but there have been some.
04 1/2 LLY 310HP, 590 torque, some overheating problems
05 LLY, 310HP,605 torque(i think)
06 LBZ, 360HP,650 torque
04 1/2 LLY 310HP, 590 torque, some overheating problems
05 LLY, 310HP,605 torque(i think)
06 LBZ, 360HP,650 torque