The new optional engine on Silverado and Sierra also beats out the 15 mpg in the city and 21 mpg on the highway yielded by the 5.0L V-8 engine in two-wheel-drive versions of the F-150 and the 14 mpg in the city and 20 on the highway provided by a 4.7L V-8 engine in two-wheel drive versions of Ram.
The 5.3L EcoTec3 two-wheel-drive mileage compares with 16 in the city and 22 on the highway for the Ford F-150 two-wheel-drive version equipped with an EcoBoost V-6 engine.
The company also is developing four-wheel-drive technology that powers two wheels with an internal combustion engine and two with an electric motor, eliminating the need for a drive train that takes up floor space, Ho said.