Downsizing has become familiar across the auto industry, with large naturally aspirated engines increasingly replaced by smaller turbocharged alternatives. General Motors is taking a rather different approach with the next generation of its full-size pickups.
The company’s sixth-generation Small Block V8 family is heading into the 2027 Chevrolet Silverado 1500 and GMC Sierra 1500. Rather than shrinking, both of the truck-focused V8s have actually grown.
The familiar 5.3- and 6.2-liter engines make way for new 5.7- and 6.6-liter units, bringing the classic 350- and 400-cubic-inch displacements back to GM’s Small Block family. Naturally, the extra displacement comes with significantly more muscle.
GM says the new engines deliver improvements in power, capability, and efficiency while retaining fundamentals that date back decades. Both will reach dealerships with the next-generation Silverado and Sierra later this year.
5.7 Liters Now Gets You 402 HP
The new L76 5.7-liter produces 402 horsepower and 428 lb-ft of torque. That’s an increase of 47 hp and 45 lb-ft over the outgoing 5.3-liter V8’s 355 hp and 383 lb-ft.
The larger L78 6.6-liter makes an even bigger jump, producing 481 hp and 501 lb-ft. Compared with the outgoing 6.2-liter’s 420 hp and 460 lb-ft, that’s another 61 horses and 41 lb-ft.
GM claims the 6.6 is the most powerful naturally aspirated V8 in its segment. Forced-induction and hybrid competitors can still produce larger numbers, but 481 hp from a naturally aspirated pickup engine isn’t exactly subtle.
GM Didn’t Just Increase Displacement
Both engines retain the Small Block family’s traditional 4.4-inch bore spacing, but GM increased piston stroke by 6 mm to achieve the additional displacement. Higher compression ratios, larger throttle bodies, and redesigned intake manifolds help take advantage of the increased airflow.
Another major change is a dual-fuel setup combining direct and port injection. GM says this gives engineers greater flexibility to optimize power, efficiency and emissions depending on operating conditions.
The lubrication system has also been heavily redesigned, featuring a continuously variable oil pump, integrated oil cooler and revised oil passages. That’s particularly noteworthy following well-publicized problems with some previous-generation 6.2-liter engines, although GM describes the Gen-6 unit as a new architecture rather than simply a fix for its predecessor.
Before the new trucks reach customers, GM expects its development fleet to complete over 1.5 million miles of real-world validation.
The Smaller V8 Is The Towing Champ
Interestingly, choosing the biggest V8 doesn’t deliver the highest maximum towing capacity. A properly equipped Silverado 1500 with the 5.7-liter can tow up to 13,700 pounds, while the equivalent Sierra reaches 13,500 pounds.
The 6.6-liter tops out at 9,700 pounds in the Silverado and 9,400 pounds in the Sierra, depending on configuration. Every engine in the 2027 light-duty truck lineup will be paired with a 10-speed automatic.
GM may be investing heavily in electrification, but the Small Block clearly isn’t heading into retirement. After more than 70 years, its latest evolution arrives with larger displacement, substantially more horsepower, and old-school numbers enthusiasts will recognize immediately: 350 and 400.