GMPartsGiant.com offers the wholesale prices for genuine 2013 GMC Sierra 3500 HD Denali 4WD parts. Parts like Engine Assembly-Manifolds & Fuel Related Parts are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 8 Cyl 6.0L Flex, 8 Cyl 6.6L Diesel. Model Code: 1 TON CREW CAB, CREW CAB 1 TON, CREW CAB 1 TON 137.0.