General Motors is not walking away from gasoline engines—or the V8. The automaker has unveiled two sixth-generation Small Block V8s for the redesigned 2027 Chevrolet Silverado 1500 and GMC Sierra 1500, along with a substantially upgraded TurboMax four-cylinder. All three gasoline engines will be paired with a 10-speed automatic transmission.
The headline engines are the new L76 5.7-liter V8 and L78 6.6-liter V8, which replace the current 5.3-liter and 6.2-liter V8s. The 5.7-liter displaces 350 cubic inches, while the 6.6-liter checks in at 400 cubic inches—two numbers that should bring back memories for longtime Chevrolet fans.
Both engines are part of GM’s sixth-generation Small Block family, which debuted with the 6.7-liter LS6 developed for the 2027 Chevrolet Corvette Stingray, Grand Sport and Grand Sport X. Despite the new technology, GM retained one of the Small Block’s fundamental dimensions: 4.40-inch spacing between cylinder bore centers, a measurement shared with more than 100 million Small Block engines produced since 1955.
The L76 5.7-liter produces 402 horsepower and 428 pound-feet of torque. That is an increase of 47 horsepower and 45 pound-feet over the outgoing 5.3-liter V8. When properly equipped, the Silverado 1500 with this engine can tow as much as 13,700 pounds. The Sierra 1500’s corresponding maximum is 13,500 pounds.
The larger L78 6.6-liter generates 481 horsepower and 501 pound-feet of torque. GM calls it the most powerful naturally aspirated V8 offered in the light-duty pickup segment. Compared with the outgoing 6.2-liter, that represents an increase of 61 horsepower and 41 pound-feet of torque.
Interestingly, the maximum published towing rating for the 6.6-liter is 9,700 pounds in the Silverado and 9,400 pounds in the Sierra—lower than the ratings attached to the 5.7-liter. Those numbers are based on the specific configurations in which the engines are offered; GM notes that towing and payload ratings vary by body configuration, trim and equipment.
GM increased the displacement of both engines by lengthening piston travel, or stroke, by 6 millimeters. The company also raised the compression ratio, enlarged the throttle diameter and developed new intake manifolds with tuned runners to handle the additional airflow.
Another major change is a dual-fuel system combining direct injection and port fuel injection. GM says the two systems allow the engines to operate more frequently within their optimum ranges for power, efficiency and emissions.
The lubrication system was also redesigned. It includes a continuously variable oil pump, an engine-mounted oil cooler and revised oil-feed locations intended to provide more consistent oil pressure.
GM says the two new V8s are being validated for the full range of pickup duties, including towing, hauling, commuting and off-road driving. The company expects its development teams to complete more than 1.5 million miles of real-world, on-road testing before the trucks reach dealerships.
The smaller gasoline engine also receives meaningful changes. The enhanced 2.7-liter TurboMax four-cylinder now produces 350 horsepower and 455 pound-feet of torque, increases of 40 horsepower and 25 pound-feet. Updates include a new turbocharger, upgraded fuel-injection system, redesigned pistons and improved active thermal management. Its maximum towing rating is 9,400 pounds.
The four-cylinder’s previous eight-speed transmission is replaced by a 10-speed automatic, which GM says will provide smoother shifts, stronger power delivery and improved towing performance. The two V8s and returning 3.0-liter Duramax turbo-diesel also use 10-speed automatics.
Production of the 5.7-liter and 6.6-liter V8s will take place at GM plants in Flint, Michigan; Tonawanda, New York; and St. Catharines, Ontario. GM previously announced an $888 million investment at Tonawanda and a C$691 million investment at St. Catharines to support sixth-generation V8 production.
The new gasoline engines will arrive with the next-generation Silverado 1500 and Sierra 1500 later this year. Pricing and additional vehicle details will be announced closer to launch. The V8, it appears, is not merely surviving at GM. It has received another generation—and a larger set of lungs.
Photo: General Motors.