GMPartsGiant.com offers the wholesale prices for genuine 2012 GMC Sierra 3500 HD Denali 2WD parts. Parts like Intake Manifold Shield/Covers 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: CREW CAB 1 TON, CREW CAB 1 TON 119.0, EXTENDED CREW CAB 1 TON 161.5.