GM Finally Shares Power Figures for Its New Small-Block V-8sCar and DriverJack FitzgeraldThu, September 17, 2026 at 2:00 PM UTCAdd us on GoogleGM Confirms Specs for Its New Small-Block V-8sGeneral MotorsGeneral Motors has released the first specs of the sixth-generation small-block V-8 engines designed for the brand's light-duty pickup trucks.The 5.7-liter V-8 makes 402 horsepower and 428 pound-feet of torque, and the 6.6-liter V-8 makes 481 horses and 501 pound-feet.Both engines will be available for the first time with the new 2027 Chevy Silverado 1500 and GMC Sierra 1500, which are scheduled to arrive by the end of the year.For those who live and die by the bow-tie badge or three-letter script on the front of their trucks, this is a momentous occasion. General Motors has finally revealed the specifications of its pickup-bound sixth-generation small-block V-8 engines.The sixth-gen small-blocks technically debuted earlier this year with the launch of the LS6-equipped 2027 Corvette Stingray and Grand Sport models, but now we've got the deets on the Silverado 1500 and Sierra 1500-bound L76 and L78 variants. Find a drink suitable to mark the occasion and read on.General MotorsBoth engines share 4.4-inch bore spacing and retain a cam-in-block design with rocker arms and two valves per cylinder. They've got a higher compression ratio than the outgoing small-blocks, leading to more efficient combustion. Larger throttle diameters allow for more airflow into the engine, with redesigned intake manifolds to handle the extra flow.AdvertisementAdvertisementThe smaller of the two thumpin' eights is a 5.7-liter that makes 402 horsepower and 428 pound-feet of torque. That's considerably more powerful than the outgoing 5.3-liter V-8, which mustered a comparably paltry 355 horsepower and 383 pound-feet.General MotorsThe new 5.7-liter mill is joined by a 6.6-liter unit called the L78. It produces 481 horsepower and 501 pound-feet of torque; compare that with the old 6.2-liter engine's 420 ponies and 460 pound-feet. GM hasn't provided any acceleration figures yet, but we're confident the L78 will be a scorcher of an engine.Sticking with the 6.6-liter powerplant, the smaller displacement comes from a slightly shorter stroke on the truck engine, versus the Corvette's 6.7-liter LS6, GM's engineers told Car and Driver at a background event. The same engineers told us that the Corvette's larger displacement is a result of chasing more performance and accepting some equipment changes that wouldn't have passed muster for the trucks.ChevroletThe 2027 lineups for both trucks will also be available with a standard 2.7-liter turbo four, which has been upgraded with a new turbocharger, redesigned pistons, a revised fuel-injection system, and better active thermal management. Those help increase output by 40 horsepower and 25 pound-feet of torque, with the engine now peaking at 350 horses and 455 pound-feet. The available Duramax diesel 3.0-liter straight-six still makes 305 hp and 495 pound-feet, but GM says it has also been tweaked to improve performance and reliability.GMCRegardless of the engine, every GM light-duty truck now features a 10-speed automatic transmission. Both the new Silverado 1500 and Sierra 1500 can tow at least 9400 pounds, though the diesel versions are capable of 12,000 and 12,100 pounds, respectively. For those who want to pull the biggest loads, the 5.7-liter-equipped Chevy peaks at 13,700 pounds, while its GMC counterpart can handle 13,500 pounds. Those max figures are both slightly more than the outgoing versions, with the Silverado capped at 13,300 pounds and the Sierra capped at 13,100 pounds.➡️ Skip the lot. Let Car and Driver help you find your next car.Shop New Cars Shop Used CarsYou Might Also LikeGift Guide: Best Ride-On Electric Cars for KidsFuture Cars Worth Waiting For: 2025–2029