GM’s New 481-HP 6.6-Liter V8 Powers the 2027 Silverado and SierraMotorBiscuitAlex HarringtonFri, September 18, 2026 at 12:00 PM UTCAdd us on GoogleGeneral Motors has revealed the engine figures for its next-generation 2027 Chevrolet Silverado 1500 and GMC Sierra 1500, and the big number everyone wants to know is 481 horsepower. That output comes from the new L78, a 6.6-liter naturally aspirated V8 that GM calls the most powerful engine of its type in the light-duty truck segment.The L78 arrives alongside the L76, a 5.7-liter V8 producing 402 hp and 428 lb-ft of torque. Both engines belong to GM's Gen-6 Small Block family and are scheduled to reach dealers with the redesigned Silverado and Sierra later in 2026.Pricing and exact sale dates remain future announcements.2027 Chevrolet Silverado 1500 Trail Boss in Trillium Metallic. Exterior passenger front 3/4 beauty shot.Two New V8s, One Familiar FoundationThe latest engines maintain a bore-center spacing of 4.40 inches, a specification that has been utilized in over 100 million engines since its introduction in 1955. GM is also bringing back the familiar 350- and 400-cubic-inch labels through the metric equivalents of 5.7 and 6.6 liters. The increase in engine displacement is achieved by extending the piston stroke by 6 millimeters compared to the previous 5.3- and 6.2-liter V8 models.AdvertisementAdvertisementAccording to GM, the new design features elevated compression ratios, larger throttle bodies, and intake manifolds designed with optimized runner lengths. The engines uses a combination of direct and port fuel injection to up performance, fuel efficiency, and reduce emissions. Their lubrication hardware includes a continuously variable oil pump, an engine-mounted oil cooler, and revised oil-feed routing."These new V8 engines advance GM's legendary Small Block architecture with greater capability, more advanced technology and the strength of GM's manufacturing footprint behind them," said Tom Bishop, GM's chief engineer for Small Block engines. "They're engineered to provide truck customers the confidence and performance they expect from a GM V8."The L76 carries GM's higher published tow figures: up to 13,700 pounds in a Silverado and 13,500 pounds in a Sierra. Its maximum payload ratings are 2,170 and 2,140 pounds, respectively. The stronger L78 reaches 9,700 pounds of Silverado towing and 9,400 pounds in the Sierra, with maximum payloads of 1,510 and 1,450 pounds. Those numbers can change a little with configuration, trim, and available packages.2027 Chevrolet Silverado 1500 ZR2 Bison in Apex Red shown in a desert setting.AdvertisementAdvertisementGM's engineering teams plan to complete over 1.5 million miles of testing on public roads before the trucks are made available for sale. That testing covers towing, hauling, commuting, and off-road use. Chevrolet executive chief engineer Mark Dickens previously said, "We pushed these engines through an extensive testing and validation process to make sure they deliver the durability, capability and dependability Silverado customers expect."What Else Is Under the Hood?The V8s are part of a four-engine lineup. The updated TurboMax four-cylinder makes 350 hp and 455 lb-ft, while the returning 3.0-liter Duramax turbo-diesel produces 305 hp and 495 lb-ft. Every engine in the 2027 Silverado and Sierra range uses a 10-speed automatic transmission.A 34-gallon, or approximately 129-liter, tank will be available with both V8s. When paired with the Duramax, GM estimates more than 900 miles of highway range using an estimated 27 mpg on a two-wheel-drive truck. Actual range depends on the vehicle.Initial assembly of the L76 and L78 engines will take place at Flint Engine Operations in Michigan, utilizing both domestic and international components. Tonawanda Propulsion in New York and St. Catharines Propulsion in Ontario are planned for additional production capacity. GM has allocated $888 million for the production of Gen-6 V8 engines in Tonawanda and C$691 million for the St. Catharines facility, as part of a larger $9 billion investment in U.S. manufacturing, which includes spending on transmissions and truck production.AdvertisementAdvertisementGM is also using the LS6 6.7-liter V8 in the 2027 Corvette Stingray, Grand Sport, and Grand Sport X, while GM Powered Solutions adapts Small Block engineering for marine applications and Chevrolet Performance continues selling Small Block, LS/LT, and racing crate engines.GM is clearly not treating the V8 as a museum piece. It is enlarging the formula, adding modern fuel and thermal-management systems, and putting the result into the trucks buyers actually use. The 6.6-liter's 481 hp gives the Silverado and Sierra a serious naturally aspirated bragging right, while the 5.7-liter looks like the more useful choice for customers who prioritize towing and payload.
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