Despite the GMC Yukon Denali's size and weight, our test vehicle's 6.2-liter V8 had no problems pushing around the condo-sized SUV thanks to 380 horsepower and 415 lb.-ft. of torque. Power was run through a smooth-shifting six-speed automatic transmission that kept the engine in its optimal rev range. There was the occasional dead spot in pedal response but we weren't sure if it was the transmission or a flaw in the drivetrain. The main downside to the Denali's engine was its thirst for fuel: Our combined number was a mere 11.5 mpg. A smaller 4.8-liter V8 engine equipped with a four-speed automatic transmission is standard on the regular Yukon, but we question whether it could deliver better fuel economy considering its low 305 lb.-ft. torque rating combined with the Yukon's weight and size.