Styling doesn't take a hit with the shorter shape, and arguably, it looks more athletic without so much metal between the wheels. The length is the only real difference, with the rest of the sheetmetal just as chisled on the bigger version. Interestingly, this gas-powered Sierra HD still has a big hood scoop from its diesel sibling. On the current GM heavy duty trucks, only the diesel models get a scoop, and it's specifically for getting more cool air to the intake. The Silverado HD may continue this differentiation, but GMC is clearly keeping it for all models.
When the Sierra HD goes on sale this summer, it will be available with either a 6.2-liter gasoline V8 like in this truck, or a 6.6-liter turbodiesel V8 making 445 horsepower and 910 pound-feet of torque, the same as the current model. All models get bedside steps, and the MultiPro tailgate is available either as standard or an option with all trims.