General Motors will offer an 8.3-liter Duramax V8, called the Mongoose, in its 2027 heavy-duty Silverado HD and Sierra HD trucks, escalating direct competition with Ford's 6.7-liter Power Stroke, internally known as Scorpion. The automaker teased the new engine and a mongoose-versus-scorpion motif but withheld technical details, leaving power, torque, towing and payload figures unrevealed for now.
The teaser confirms the displacement and the V8 turbo-diesel layout but stops short of output claims. Industry observers expect the new Duramax to match or exceed Ford's Power Stroke, which is rated at 500 horsepower and 1,200 pound-feet of torque. The Mongoose will succeed GM's current 6.6-liter Duramax V8, the existing unit that produces 470 horsepower and 975 pound-feet of torque.
If GM's new V8 tops Ford's numbers, it would also move past Ram's 6.7-liter Cummins inline-six, which develops 430 horsepower and 1,075 lb-ft of torque. Beyond powertrain changes, GM plans styling updates for its heavy-duty pickups, drawing design cues from the 2027 Silverado 1500 and GMC Sierra 1500 as the HD models are refreshed.
The teaser's animal imagery underlines the competitive intent: the Mongoose name targets the Scorpion codename used inside Ford. General Motors has not published timelines beyond placing the engine into 2027 model-year trucks, and the Silverado HD and Sierra HD could debut before the end of the year. Until GM releases full specifications, fleet buyers and owners who prioritise towing and payload will have to wait to compare official figures and real-world capability.
The introduction of an 8.3-liter Duramax for 2027 signals that GM plans to press on horsepower and torque as key battlegrounds in the heavy-duty pickup market. The company is replacing its existing Duramax V8, so the arms race among diesel powertrains for work-focused buyers is set to continue once GM publishes the Mongoose's numbers.
