The new 5.3L EcoTec3 V-8
355 hp and 383 lb-ft of torque
Sierra’s new 5.3L offers a class-leading towing capacity of up to 11,500 pounds
EPA estimates of 16 mpg city and 23 highway with two-wheel drive or 16/22 with four-wheel drive


Here is the link to full article and additional info http://media.gmc.com/media/us/en/gmc...01-sierra.html