What Does a Denali Have That an At4 Doesn't?
Both the Trail Boss and the AT4 use the 5.3 EcoTec3 V8 as their base engine. This gives them 355 horsepower and 383 pounds of torque, though you can upgrade to the 6.2L V8. The upgraded V8 will give you 420 horsepower. However, the AT4 gives you the option of a 3.0L I-6 Duramax diesel engine.
