General Motors is giving traditional V8 truck buyers plenty to look forward to with its sixth-generation small-block engines, and we finally have the numbers that matter. The new 5.7-liter and 6.6-liter V8s are headed for the redesigned 2027 Chevrolet Silverado 1500 and GMC Sierra 1500, replacing the familiar 5.3-liter and 6.2-liter engines that have powered millions of GM trucks. According to Car and Driver, the new 5.7-liter L76 produces 402 horsepower and 428 pound-feet of torque, while the larger 6.6-liter L78 steps up to an impressive 481 horsepower and 501 pound-feet. Both trucks are expected to reach dealerships before the end of 2026.
Those numbers represent a healthy jump over the outgoing engines. The previous 5.3-liter V8 made 355 horsepower and 383 pound-feet of torque, meaning the new 5.7 adds 47 horsepower and 45 pound-feet. Moving up the range, the 6.6-liter delivers 61 more horsepower and 41 additional pound-feet compared with the outgoing 6.2-liter V8. That should give buyers a noticeable performance gain without forcing GM to abandon the naturally aspirated V8 formula that continues to resonate with pickup owners. Chevrolet has also said the new Silverado will be its most powerful production Silverado yet.
GM has not simply increased displacement and called it a day. The sixth-generation small-block architecture retains the traditional cam-in-block layout, rocker arms, two valves per cylinder and GM’s familiar 4.4-inch bore spacing, but several important areas have been reworked. Higher compression ratios are designed to improve combustion efficiency, while larger throttle bodies and redesigned intake manifolds allow the engines to breathe more freely. The result is a thoroughly updated version of a formula GM has been refining for generations rather than a dramatic departure from the small-block V8 enthusiasts already know.
The 6.6-liter L78 is especially interesting because it shares some of its underlying engineering with the newer Corvette small-block family while being tailored specifically for truck duty. Car and Driver reports that GM engineers used a slightly shorter stroke for the truck engine compared with the Corvette’s 6.7-liter LS6. That decision illustrates how different the priorities are between the two applications. Corvette engineers can chase maximum performance, while a Silverado or Sierra engine also has to account for towing, payload, heat management, durability and the countless hours owners may spend working their trucks.
For GM, keeping two new naturally aspirated V8s in the Silverado and Sierra lineup is significant at a time when several competitors have leaned harder into turbocharged and electrified powertrains. The returning 2.7-liter TurboMax four-cylinder and 3.0-liter Duramax diesel will still give buyers alternatives, but the new 5.7-liter and 6.6-liter engines make it clear that the V8 remains an important part of Chevrolet and GMC’s full-size truck strategy. We will need real-world driving, towing and fuel economy figures before knowing the full story, but with as much as 481 horsepower and 501 pound-feet on tap, GM’s next generation of small-block truck engines is arriving with considerably more muscle than the V8s it replaces.
