09/17/2026
Four powertrain options, two all-new V8s, and a diesel that can travel more than 900 miles between fuel stops. GM shared plenty of engine news in Flint, Mich., where we attended the unveiling and toured the company's engine manufacturing facility.
The new lineup will power the 2027 Chevrolet Silverado 1500 and GMC Sierra 1500. The centerpiece is GM's sixth-generation small-block V8 architecture, featuring two all-new engines:
• 5.7L V8: 402 HP and 428 lb.-ft. of torque. A properly equipped Silverado can tow up to 13,700 pounds, while the Sierra reaches 13,500 pounds.
• 6.6L V8: 481 HP and 501 lb.-ft. of torque, making it the most powerful naturally aspirated V8 in its segment, according to GM.
More than displacement changed. Both engines feature a redesigned architecture with higher compression ratios, improved airflow, and a dual-fuel system combining direct and port fuel injection. A new lubrication system incorporates a continuously variable oil pump, on-engine oil cooler, and revised oil feed locations to improve oil pressure consistency.
"Fundamentally, it's a lot more than just a bigger engine," said Mark Dickens, GM's executive chief engineer for full-size trucks and SUVs, during the unveiling.
And GM didn't stop with the V8s.
The enhanced 2.7L TurboMax four-cylinder gains 40 HP and 25 lb.-ft. of torque, bringing output to 350 HP and 455 lb.-ft. An upgraded turbocharger accounts for much of the increase, but Dickens emphasized that the additional horsepower extends across a 1,000-rpm range, rather than appearing only at peak output.
The returning 3.0L Duramax inline-six diesel retains its 305 HP and 495 lb.-ft. of torque, while receiving several updates aimed at improving performance and reliability.
Then there's that range we talked about.
With an available 34-gallon fuel tank, GM estimates the diesel can exceed 900 miles of highway driving in a two-wheel-drive configuration. That's based on an estimated 27 highway mpg, with actual range varying. GM also increased DEF tank capacity by two gallons, or 37%, to help reduce interruptions on longer trips.
All four engines will be paired with a 10-speed automatic transmission.
Beyond the performance figures, GM detailed its redesigned engine architecture, expanded manufacturing quality controls, and extensive validation efforts. The company expects to complete more than 1.5 million miles of real-world, on-road testing before the trucks reach dealerships later this year.
Production of the new V8s will begin at Flint Engine Operations, with additional capacity planned in New York and Ontario.
We take a closer look at the engineering, capability, and manufacturing behind GM's next generation of light-duty engines, including insights from the unveiling and plant tour. https://bit.ly/4Ao81nW
# Engines