The Sierra, sibling to GM's best-selling Chevy Silverado full-size pickup and a strong seller for GM, is available in half-, three-quarter- and one-ton models, two-wheel drive and four-wheel drive, Regular, Extended and Crew Cab bodies and a number of style and trim variations. Engine choices include a 4.3-liter V6; 4.8-, 5.3- and 6.0-liter Vortec gasoline V8s; and both mild hybrid and flex fuel E85 (ethanol/gasoline blend-compatible) versions of the 5.3-liter V8.