GM unveils 555-hp 8.3-liter Duramax Mongoose diesel V8 — Motor1

General Motors has unveiled a new 8.3-liter Duramax V8 turbodiesel engine called Mongoose. It produces 555 horsepower and 1,230 pound-feet of torque. As Motor1 reports, the new unit will be installed in the 2027 model-year Chevrolet Silverado HD and GMC Sierra HD heavy-duty pickups.

Power of the new Duramax

The new engine surpasses the previous-generation 6.6-liter Duramax, which delivers 470 horsepower and 975 pound-feet of torque. According to the publication, the Mongoose also has higher horsepower and torque figures than the diesel Ford Power Stroke: 500 horsepower and 1,200 pound-feet, respectively.

GM will offer the 8.3-liter V8 for the Chevrolet Silverado HD and GMC Sierra HD. When properly equipped, the pickups will be able to tow up to 20,000 pounds with a conventional trailer setup.

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Towing up to 38,000 pounds

For vehicles with an in-bed gooseneck trailer setup, the maximum towing capacity is stated at 38,000 pounds. Both models will also receive electric power steering. According to GM, it is intended to provide more precise steering and reduce steering-wheel kickback and noise levels.

The manufacturer increased the size of the brakes and fitted four-piston calipers at the front. The pickups will also feature improved turbocharging and cooling technologies. The 2027 model-year Chevrolet Silverado HD and GMC Sierra HD are expected to arrive at dealerships later in 2026.