GM Teases 8.3L Duramax Mongoose V8 for Silverado HD
The diesel engine wars just got bigger. General Motors has confirmed an all-new 8.3-liter Duramax turbo-diesel V8 for its next heavy-duty trucks, and it gave the engine a name aimed directly at Ford: Mongoose.
GM had already signaled that new powertrains were coming to its heavy-duty lineup. Now, a short teaser video gives us the first official look at the diesel engine expected to power future Chevrolet Silverado HD and GMC Sierra HD models.
The Mongoose Targets Ford’s Power Stroke
The name is not subtle. Ford uses Scorpion as the internal codename for its 6.7-liter Power Stroke V8, so GM’s teaser opens with a scorpion moving across the desert. A mongoose soon appears, setting up a predator-versus-prey theme before GM reveals the engine.
GM calls the new powerplant “the all-new 8.3L Duramax turbo-diesel V8” and says it is “built to dominate.” That is bold language, but the company has not released horsepower, torque, towing capacity, or fuel economy estimates yet.
The current 6.6-liter Duramax V8 in the Silverado HD produces 470 horsepower and 975 lb-ft of torque. The Mongoose adds substantial displacement, but engine size alone does not guarantee a specific output. Until GM publishes the numbers, claims that it will beat Ford or Ram remain speculation.
Will Chevrolet Get the 8.3L Duramax First?
The teaser also appears to favor Chevrolet. A bowtie shape forms the mongoose’s eyes just before it attacks, while a GMC logo appears as a shadow near a tree. That could be GM’s way of hinting that the Silverado HD will receive the 8.3L Duramax before the Sierra HD.
For now, that is only a theory. GM has not announced which truck will launch the engine, when production will begin, or whether Chevrolet and GMC will get it at the same time. The company’s redesigned 2027 Chevrolet Silverado 1500 and 2027 GMC Sierra 1500 offer a preview of the styling and technology likely to influence the next HD updates.
A Big Diesel Arrives as Fuel Prices Surge
Timing may become the Mongoose’s biggest challenge. AAA listed the national average for diesel at $6.51 per gallon on September 21, 2026, a record high and about $2.81 more than a year earlier. Buyers who tow heavy loads may still value diesel torque and range, but fuel cost will be harder to ignore.
Most heavy-duty pickups with a gross vehicle weight rating above 8,500 pounds are not required to carry EPA fuel economy ratings. That makes real-world efficiency especially important. GM will need to show that the Mongoose delivers enough capability, range, and durability to justify feeding a larger diesel V8.
The 8.3L Duramax Mongoose V8 has already done its first job: it has everyone talking. The next step is proving that the engine’s output and capability can live up to one of the boldest truck teasers GM has released in years.