General Motors has disclosed the specifications of its sixth-generation small-block V-8 powerplants slated for the 2027 Silverado 1500 and Sierra 1500 pickups.
New V-8 Powertrains
The 5.7-liter unit delivers 402 horsepower and 428 pound-feet of torque, surpassing the prior 5.3-liter version’s 355 hp and 383 lb-ft.
The larger 6.6-liter model, designated L78, produces 481 horsepower and 501 pound-feet of torque, an increase over the former 6.2-liter’s 420 hp and 460 lb-ft.
Both powerplants share a 4.4-inch bore spacing, a cam-in-block layout with rocker arms, and two valves per cylinder. A higher compression ratio and larger throttle openings improve combustion efficiency and airflow.
According to engineers, the 6.6-liter’s shorter stroke accounts for its smaller displacement compared with the Corvette’s 6.7-liter LS6, which was tuned for maximum performance.
These engines will appear in the 2027 Silverado 1500 and Sierra 1500, both expected to reach showrooms before year-end.
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L76 and L78 Pickup Variants and Updated Capacity Limits
General Motors disclosed the technical data for the pickup-oriented sixth-generation small-block V-8s. The engines first appeared earlier this year in the LS6-equipped 2027 Corvette Stingray and Grand Sport. The new L76 and L78 versions are slated for the 2027 Silverado 1500 and Sierra 1500 models. They continue the sixth-generation design language introduced earlier in the Corvette line.
Engine Options and Capabilities
A 2.7-liter turbocharged four-cylinder also returns, now featuring a new turbo, revised pistons, and enhanced fuel injection, raising output to 350 horsepower and 455 pound-feet of torque.
The existing 3.0-liter Duramax diesel continues to generate 305 horsepower and 495 pound-feet of torque, with refinements aimed at durability.
All configurations are paired with a 10-speed automatic transmission.
Maximum towing capacities climb to 13,700 lb for the Chevrolet variant and 13,500 lb for the GMC counterpart when equipped with the 5.7-liter unit. Diesel-powered versions can handle 12,000 lb and 12,100 lb respectively, while every model maintains a baseline capacity of at least 9,400 lb.
