General Motors detailed new 5.7-liter and 6.6-liter V8 engines for 2027 full-size pickups

General Motors has officially revealed detailed specifications for two new V8 engines scheduled to power its next-generation full-size pickup trucks. The 2027 Chevrolet Silverado 1500 and GMC Sierra 1500 will receive two distinct versions of GM's sixth-generation Small Block V8 engine architecture: a 5.7-liter unit designated L76 and a 6.6-liter unit designated L78. GM had previously previewed these engines during the debut of its redesigned pickups earlier in the year, but full technical data has now been made public.

The 5.7-liter L76 V8 serves as the replacement for the outgoing 5.3-liter V8. Engineers increased displacement to 350 cubic inches by lengthening the engine stroke by 6.0 millimeters. The updated motor produces 402 horsepower and 428 pound-feet of torque, representing substantial gains of 47 horsepower and 45 pound-feet compared to the previous 5.3-liter power unit. Key mechanical revisions include a higher compression ratio, enlarged throttle bodies, and redesigned intake manifolds equipped with tuned runners to enhance airflow. Like other members of the sixth-generation Small Block family, the 5.7-liter utilizes both direct and port fuel injection.

Despite having smaller displacement than the L78, the 5.7-liter L76 is engineered to deliver maximum towing capability. When properly equipped, a 2027 Chevrolet Silverado 1500 with the 5.7-liter V8 can tow up to 13,700 pounds, while the equivalent GMC Sierra 1500 is rated to pull up to 13,500 pounds. Maximum payload capacity reaches 2,170 pounds in the Silverado and 2,140 pounds in the Sierra.

Sitting at the top of the truck lineup is the new 6.6-liter L78 V8, which succeeds the outgoing 6.2-liter V8. With 400 cubic inches of displacement, the L78 generates 481 horsepower and 501 pound-feet of torque, delivering an increase of 61 horsepower and 41 pound-feet over the engine it replaces. Because this engine is aimed primarily at buyers prioritizing performance and premium equipment rather than maximum hauling utility, its tow rating is lower than that of the 5.7-liter: the Silverado is rated for up to 9,700 pounds and the Sierra for up to 9,400 pounds. Maximum payload ratings stand at 1,510 pounds for the Silverado and 1,450 pounds for the Sierra.

Although the truck-oriented L78 shares GM's standard 4.40-inch bore spacing with the 6.7-liter LS6 V8 utilized in the 2027 Corvette, the truck powertrains are specifically calibrated for heavy towing, payload hauling, and off-road driving. Manufacturing will initially take place at GM's Flint Engine Operations, with future assembly planned at Tonawanda Propulsion in New York and St. Catharines Propulsion in Canada. Both V8 engines will become available when the next-generation Silverado 1500 and Sierra 1500 launch later this year.