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2027 Silverado and Sierra Engines: V8 Power, Towing and New Oil Checks
Description
GM’s new 5.7- and 6.6-liter V8s add power while retaining cylinder deactivation. Towing figures, oil checks and diesel range round out the changes.
GM’s 2027 Chevrolet Silverado 1500 and GMC Sierra 1500 will offer two new V8s, but the biggest ownership changes sit alongside the headline power figures. The engines replace the current 5.3- and 6.2-liter V8s, keep Dynamic Fuel Management, add port injection and require drivers to check oil level through the cabin screen instead of using a dipstick.
The engineering details came from GM’s powertrain event in Flint, Michigan. The company also outlined updates to its TurboMax and Duramax engines, though fuel-economy figures for the new V8-powered trucks and pricing for the model year remain unannounced. More details are expected before the trucks reach dealerships later this year. Earlier coverage raised questions about Silverado specifications and covered the 2027 Sierra reveal.
Two V8s, with a towing surprise
The 5.7-liter L76 replaces the 5.3-liter, while the 6.6-liter L78 takes over from the 6.2-liter. Both remain part of GM’s Small Block family, retaining its 4.40-inch spacing between cylinder bore centers. GM increased piston stroke by 6 millimeters, raised compression ratios, enlarged throttle openings and developed intake manifolds with tuned runners.
The L76 makes 402 horsepower and 428 pound-feet of torque. The L78 delivers 481 horsepower and 501 pound-feet, which GM describes as the highest output from a naturally aspirated V8 in the light-duty truck segment.
Yet the 5.7-liter has the higher maximum tow rating. A properly equipped Silverado with that engine is rated for up to 13,700 pounds, against 9,700 pounds for the highest-rated 6.6-liter Silverado configuration. Sierra figures are 13,500 and 9,400 pounds, respectively. The gap is a reminder that peak horsepower alone won’t determine towing capacity; engine, configuration and available packages all matter.
| Engine | Horsepower | Torque | Max Silverado towing | Max Sierra towing |
|---|---|---|---|---|
| Enhanced TurboMax | 350 hp | 455 lb-ft | 9,400 lb | 9,400 lb |
| 3.0L Duramax | 305 hp | 495 lb-ft | 12,000 lb | 12,100 lb |
| 5.7L V8 | 402 hp | 428 lb-ft | 13,700 lb | 13,500 lb |
| 6.6L V8 | 481 hp | 501 lb-ft | 9,700 lb | 9,400 lb |
Electronic oil checks and familiar cylinder deactivation
Owners will check oil level on the infotainment screen. Randy Dufresne, design system engineer for GM’s Gen 6 Small Block engines, said the port-injection hardware and other components leave little room to route a conventional dipstick. GM replaces the dipstick and the previous low-oil-level switch with a sensor that provides a level reading and a low-oil warning. The engineers’ discussion didn’t specify the conditions needed for an accurate reading, so owners will need to follow the procedure in the vehicle manual.
Dynamic Fuel Management (DFM) also carries over. Dufresne said the system uses eight solenoids in the engine valley to direct oil to lifters and deactivate cylinders as needed. That’s the same operating design used in the current 5.3- and 6.2-liter engines, rather than a rocker-based arrangement discussed in a patent.
Older Active Fuel Management disabled the same four cylinders. DFM can deactivate any of the eight, depending on conditions. Asked about durability, Dufresne said GM builds its test schedules around the expected number of cylinder-switching events. That explains the development approach, but long-term ownership experience with these new engines is still to come.
Both V8s also use automatic engine stop/start. It shuts the engine off during certain stops; DFM instead changes which cylinders fire while the engine is running. The two features address different operating situations.
Reworked oiling and dual injection
The new lubrication system pairs a continuously variable-displacement oil pump with an oil cooler integrated into the pan and revised oil passages. Dufresne described a pump that adjusts flow and pressure to driving conditions, with the aim of supplying what the engine needs while reducing the energy used to drive the pump.
The changes also include larger lifter oil galleries, larger dual feeds to the main bearings and machined passages intended to improve cleanliness and avoid residual casting sand. Dufresne clarified that the larger passages are designed to deliver oil efficiently where it’s needed, rather than to flush out debris. He specified 0W-30 for the 6.6-liter, saying its 30-grade oil supports the bearing oil film while meeting fuel-consumption targets.
Both V8s combine direct and port fuel injection. Dufresne said port injection wasn’t added to address intake-valve carbon buildup; future emissions requirements drove the decision. GM says the combined system gives it more scope to optimize power, efficiency and emissions. The company did not provide final truck fuel-economy ratings. Meeting an engine-level consumption target isn’t the same as publishing a mileage figure for a complete vehicle.
Updates for TurboMax and Duramax
The four-engine lineup also includes an updated 2.7-liter TurboMax and the returning 3.0-liter Duramax diesel. TurboMax output rises by 40 horsepower and 25 pound-feet to 350 horsepower and 455 pound-feet. Its revisions include a new turbocharger, upgraded fuel injection, redesigned pistons and changes to thermal management. A 10-speed automatic becomes standard across all four engine choices.
The Duramax produces 305 horsepower and 495 pound-feet. GM lists changes to its pistons, turbo vanes, nitrogen-oxide sensor, sealing and injector corrosion protection. Mark Dickens, executive chief engineer for GM’s full-size trucks and SUVs, said the diesel’s exhaust-fluid tank grows by 2 gallons, or 37%, and gains improved level messaging.
An available approximately 34-gallon fuel tank gives the diesel a projected highway range of more than 900 miles, GM says, based on 27 highway mpg in a two-wheel-drive configuration. That estimate isn’t for towing, and actual range will vary. The larger tank will also be available with both V8s.
Initial V8 production will take place at Flint Engine Operations, with more capacity planned at Tonawanda in New York and St. Catharines in Ontario. GM president Mark Reuss said the engines will complete more than 1.5 million miles of on-road validation before dealership arrival. For buyers, the next useful details are pricing, configurations and complete-truck fuel economy; for now, the towing table and the shift to electronic oil checks are the clearest guide to how the new engines fit the job.
The post 2027 Chevrolet Silverado, GMC Sierra V8s: More Power, No Dipstick, 350 Returns, Cylinder Deactivation Remains appeared first on Pickup Truck +SUV Talk.
