Engines and modifications Sierra 2500HD III (GMT900) Extended Cab Long Box

6.6 Duramax TD V8 (365 Hp) Automatic

6.6 Duramax TD V8 (365 Hp) 4WD Automatic

6.0 V8 (360 Hp) Automatic

6.0 V8 (360 Hp) 4WD Automatic