GM Reveals New 5.7L and 6.6L V-8s for 2027 Silverado and Sierra, Keeps Diesel

GM's Powertrain Reveal for the 2027 Silverado 1500 and Sierra 1500

General Motors has filled in the last major blank for its next-generation full-size pickups, confirming the engine range that will power the 2027 Chevrolet Silverado 1500 and GMC Sierra 1500. The 5.3-liter V-8 is replaced by a new 5.7-liter rated at 402 horsepower and 428 lb-ft of torque, while the 6.2-liter gives way to a 6.6-liter producing 481 horsepower and 501 lb-ft. Both sit on the same small-block architecture that debuted in the 2027 Chevrolet Corvette, although GM says the truck versions are tuned for towing, off-road use and long-distance driving rather than track work.

The lineup also includes a revised 2.7-liter TurboMax four-cylinder that now makes 350 horsepower and 455 lb-ft—up 40 horsepower and 25 lb-ft—and moves from an eight-speed to the 10-speed automatic. The 3.0-liter Duramax turbo-diesel inline-six remains, holding at 305 horsepower and 495 lb-ft but receiving updated pistons, turbo vanes, a revised NOx sensor and new fuel injectors. A two-gallon larger DEF tank and an optional 34-gallon fuel tank can extend range to roughly 900 miles with the diesel.

GM says maximum Silverado towing reaches 13,700 pounds with the 5.7-liter V-8, Double Cab and rear-wheel drive, edging the Ford F-150's 3.5-liter EcoBoost rating by 200 pounds. The Sierra tops out at 13,500 pounds. The most powerful 6.6-liter is reserved for higher trim levels, which GM notes reduces its maximum towing figure. Fuel-economy numbers and final pricing have not yet been published, with both expected closer to the late-2026 on-sale date.

Where the New Engine Lineup Fits in the Full-Size Truck Wars

GM's Truck Formula: More Displacement, Higher Output

GM is leaning into internal combustion as a differentiator in the half-ton segment. The new 5.7-liter adds 47 horsepower and 45 lb-ft over the outgoing 5.3-liter, while the 6.6-liter jumps 61 horsepower and 41 lb-ft above the old 6.2-liter. Compression ratios rise to 12.0:1 and 12.5:1, respectively, against the Corvette's 13.0:1, and GM has paired the larger displacement with new intake manifolds, port and direct fuel injection, and a redesigned lubrication system. The result, on paper, is the strongest naturally aspirated powertrain claim in the segment.

The Towing Leaderboard Is More Nuanced Than the Headline Number

The 13,700-pound Silverado towing figure is tied to a specific setup: the 5.7-liter V-8, Double Cab and rear-wheel drive. The highest-output 6.6-liter does not produce the highest tow rating because GM packages it with higher trims that reduce maximum towing. In practice, that means towing-focused buyers may be shopping the base V-8 rather than the range-topping engine. Against Ford, the edge is real but narrow—only 200 pounds over the 3.5-liter EcoBoost in that configuration—while the Sierra's 13,500-pound rating merely matches the Ford benchmark.

Diesel and TurboMax Cover the Work and Range Roles

The retained Duramax diesel keeps the same output but gains emissions-related hardware and a larger DEF tank, signaling that GM wants the diesel to remain viable for long highway towing without forcing owners to stop as often. The optional 34-gallon tank and up to 900-mile range figure are aimed squarely at fleet operators and long-distance towers. The base TurboMax four-cylinder, meanwhile, becomes the payload leader at 2,340 pounds and gains the 10-speed automatic, making it more than a compliance or fuel-economy fallback.

Shared Architecture, Different Mission

Using one small-block architecture across the Corvette and the full-size trucks is a clear engineering-scale play: GM can spread development across sports-car volumes and high-volume pickups while tuning heads, compression and oiling for different workloads. GM has not disclosed development cost savings, so this remains a strategic reading rather than a stated financial figure. The risk is that the reliability and efficiency claims around the new architecture remain unproven until independent towing and long-term durability testing appears after launch.

For Truck Buyers and Fleet Operators: Practical Engine Choices Before the Late-2026 Launch

For private buyers and fleet managers, the useful specificity is in configurations rather than headline horsepower.

• If maximum towing is the priority: specify the 5.7-liter V-8 with Double Cab and rear-wheel drive. GM says that combination is required for the 13,700-pound figure, so higher trims or four-wheel drive will not carry the same rating.
• If payload matters more than towing: the base 2.7-liter TurboMax is the payload leader at 2,340 pounds, and its move to the 10-speed automatic may change low-speed towing behavior compared with the previous eight-speed.
• If long-range diesel operation is the plan: check whether the optional 34-gallon fuel tank can be ordered, since GM links the up to 900-mile range to the Duramax and 34-gallon combination. The larger DEF tank also increases the interval between DEF fill-ups.
• On the 6.6-liter V-8: treat it as a performance choice rather than a towing maximum choice. GM says premium fuel is recommended but not required, but actual operating cost will depend on fuel-economy ratings that have not been published.
• On timing: pricing is not final. GM expects pricing details closer to the late-2026 on-sale date, so early purchase comparisons should treat current numbers as provisional.