Engine specifications for Chevrolet Silverados are available online at LeftLaneNews.com, Edmunds.com, Chevrolet.com and MotorTrend.com, as of 2015. There are specifications for new and used Silverados, some of which have hybrid engines.
MotorTrend.com allows the user to select the trim and style, which changes the specifications of the engine. A 2010 Silverado 1500 standard bed extended cab has a 4.3-liter V-6 engine, while the 3500 style has a 6-liter V-8. Some models 2014 models used EcoTec V-8 engines.
Edmunds.com has a drop-down menu for the dozens of different trim and style types, and about half of them come with 4.3-liter V-6 engines and half with 5.3-liter V-8s. They all have variable valve timing with between 12 and 16 overhead valves.