Sierra owners chose them because they wanted a truck that worked as hard as them. With gorgeous styling, an array of utility options, and a 5.3L V8 producing 355 HP and 383 FT-LBS of torque, Sierra is a great start to getting the job done.
While the 5.3L is powerful, it is dwarfed in comparison to the 6.6L Duramax. That’s where Bully Dog® comes in. Our calibrators have engineered the tunes to optimize the 5.3L V8 for increased horsepower and torque–so each Sierra comes ready to haul any load or cross any terrain.
With our 93 octane performance tune we’ve achieved peak power and torque gains of up to 21 HP and 24 FT-LBS (max power and torque gains of up to 26 HP and 30 FT-LBS). Along with the power and torque increases, our calibration greatly improves throttle response and firms up transmission shifts on the 6-spd for enhanced drivability.