Engines Factory supplies premium remanufactured and rebuilt Chevrolet GMC Duramax diesel engines for pickup truck, towing, commercial, fleet, industrial, and performance applications. Our inventory includes Duramax long block engines, drop-in diesel engines, rebuilt replacement engines, and complete diesel powertrain solutions engineered for reliability, durability, horsepower, torque, and exact application fitment. Popular GM Duramax diesel engine platforms include the 6.6L Duramax LB7, LLY, LBZ, LMM, LML, and L5P engines used in Chevrolet Silverado and GMC Sierra heavy-duty truck applications throughout the United States.