General Motors Co. The fully integrated, dedicated Compressed Natural Gas (CNG) option is available this fall for Chevrolet Express and GMC Savana full-size vans. Powered by a Vortec 6-liter V8 engine, the vans are equipped with hardened exhaust valves and intake and exhaust valve seats for improved wear resistance and durability with gaseous fuel systems. The vans meet all EPA- and CARB-emissions certification requirements and are covered by a three-year/36,000-mile new-vehicle limited warranty and a five-year/100,000-mile limited powertrain warranty. 800.353.3867. www.gmfleet.com.