http://VacavilleGMC.com 866-593-1568 The 2012 GMC Sierra 1500 is available with four different engine choices. In the Work trim level, the 2012 GMC Sierra is powered by a standard 4.3-liter V6 that produces 195 horsepower and 260 pound-feet of torque. Buyers may upgrade to a 4.8-liter V8 that makes 302 hp and 305 lb-ft, or a 5.3-liter V8 that's good for 315 hp and 335 lb-ft. The SLE trims will have one of the two V8s as standard, while the SLT has the 5.3-liter engine as standard.