GM Unveils Gen-6 Small Block V8 Family With Up to 481 HP for Next-Generation Trucks
New 5.7L and 6.6L engines bring more power and efficiency to GM light-duty truck lineup
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Source: GM ↗
General Motors’ sixth-generation Small Block V8 architecture delivers two new truck engines for the 2027 Chevrolet Silverado 1500 and GMC Sierra 1500, with the top-line 6.6L producing 481 horsepower, the highest output of any naturally aspirated V8 in the light-duty segment.
The new L76 5.7L and L78 6.6L units succeed the previous 5.3L and 6.2L V8s. GM engineers added 6 mm of piston stroke to reach the 5.7L (350 cubic inch) and 6.6L (400 cubic inch) displacements, and paired the change with a higher compression ratio, larger throttle diameters and new intake manifolds with tuned runners to manage the increased airflow.
The L76 5.7L is rated at 402 horsepower and 428 lb.-ft. of torque. Paired with the 2027 Silverado 1500, it supports a maximum available tow rating of 13,700 pounds and a maximum payload of 2,170 pounds; Sierra 1500 figures are 13,500 pounds towing and 2,140 pounds payload. The L78 6.6L produces 481 horsepower and 501 lb.-ft. of torque, with maximum towing of 9,700 pounds and maximum payload of 1,510 pounds on the Silverado, and 9,400 pounds towing and 1,450 pounds payload on the Sierra. All figures vary by configuration, trim and available packages.
“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, Chief Engineer for Small Block engines. “They’re engineered to provide truck customers the confidence and performance they expect from a GM V8.”
Both engines share two sixth-generation system upgrades. A dual-fuel system combines direct injection and port fuel injection to expand operation across power, efficiency and emissions windows. A new lubrication system uses a continuously variable oil pump, an on-engine oil cooler and reworked oil feed locations for improved oil pressure consistency.
The L76 and L78 complete a four-engine lineup for the next-generation Silverado 1500 and Sierra 1500. The Enhanced TurboMax, now paired with a 10-speed automatic transmission, adds 40 horsepower and 25 lb.-ft. of torque over its predecessor to reach 350 horsepower and 455 lb.-ft. of torque, with maximum towing of 9,400 pounds and maximum payload of 2,340 pounds on the Silverado and 2,310 pounds on the Sierra. Updates to the TurboMax include a new turbocharger, an upgraded fuel injection system, improved active thermal management and redesigned pistons. The Duramax 3.0L Turbo-Diesel produces 305 horsepower and 495 lb.-ft. of torque, with maximum towing of 12,000 pounds on the Silverado and 12,100 pounds on the Sierra, and maximum payload of 1,870 pounds and 1,850 pounds, respectively.
Initial production of the L76 and L78 is underway at GM’s Flint Engine Operations in Michigan, with additional capacity planned at Tonawanda and St. Catharines. GM development teams expect to log more than 1.5 million miles (2.4 million km) of real-world on-road validation before the next-generation trucks reach dealerships later in 2027.
