The standard Chevrolet Silverado 2500HD engine is a 6.0-liter V8 with variable valve timing. It is a Vortec branded engine from General Motors. When buying this truck new, there is an option to change the engine to a Duramax branded 6.6-liter turbo diesel V8.
The standard 6.0 liter engine that comes in the Chevrolet SIlverado 2500HD is E85 capable. This means it can be filled up with E85 biofuel, which is made up of 85 percent ethanol and 15 percent standard gasoline.
There are two options: a 360 horsepower version that produces 380 pounds per foot of torque, and a 320 horsepower version which produces the same torque number. The variable valve timing of the engine is designed to give it the best of both worlds, power at the upper end of the rev range and additional torque at the bottom.
The optional engine is much more powerful. It produces 397 horsepower and 765 pound per foot of torque. It also has other innovative features, such as a diesel exhaust brake. This helps to slow down the vehicle when it is on steep declines. This engine requires an engine block heater and a specific six-speed transmission made under the Allison brand.