General Motors has unveiled refreshed 2027 Chevrolet Silverado HD and GMC Sierra HD trucks, featuring an all-new 8.3-liter Duramax turbo-diesel V8. The in-house-designed engine, codenamed Mongoose, produces 555 horsepower. It delivers 1,230 lb-ft of torque, a substantial increase over the outgoing 6.6-liter diesel. The new engine puts GM in direct competition with rivals, particularly Ford’s Scorpion Power Stroke.
The 2027 trucks will feature segment-first rack-and-pinion electric power steering and a new electronic brake-boost system. GM says the upgrades are designed to improve handling and control, especially while towing. Maximum gooseneck towing capacity for the lineup rises to 38,000 pounds.
GM will build the new diesel engine at its expanded DMAX facility in Brookville, Ohio.