http://news.pickuptrucks.com/2011/07...k-engines.html

GM is expected to offer four significantly updated or new gasoline engines for the 2014 Chevrolet Silverado and GMC Sierra, in addition to the workhorse 6.6-liter Duramax diesel V-8. All of the new gas engines will feature direct injection. Heavy-duty trucks are said to receive an exclusive 6.2-liter V-8. Currently, a 6.2-liter V-8 is only available for the 2007-12 Silverado and Sierra 1500 half-tons. Light- and heavy-duty models would share a 6.0-liter V-8 thatís currently only available for 2007-2012 Silverado and Sierra HD pickups. In early planning for both large displacement V-8s, supercharging was considered as an option (similar to the 2009 Chevrolet Silverado ZR2 concept truck) for maximum power while maintaining fuel efficiency. However, supercharging has been dropped from consideration for now. GMís next-gen half-tons are also expected to continue offering a V-8 with 5.3 liters of displacement and a turbocharged six-cylinder engine that can compete head-to-head with Fordís 3.5-liter EcoBoost V-6. Six-speed transmissions are expected to be the standard gearbox for all engines.