September 21, 2026
GM’s September 17 release leads with 481 horsepower and buries the number that changes a sales conversation. Four rows down, in GM’s own powertrain quick-reference table, the L78 6.6L is rated at 9,700 pounds maximum towing on the Silverado and 9,400 on the Sierra. The L76 5.7L, with 79 fewer horsepower, is rated at 13,700 and 13,500.
2,170 pounds of payload on the 5.7L Silverado against 1,510 on the 6.6L puts the gap in the same direction. The 6.6L’s tow rating sits 300 pounds above the four-cylinder Enhanced TurboMax at 9,400 pounds and 2,300 pounds below the Duramax 3.0L diesel at 12,000. Ranked by what the truck can pull, the most powerful engine GM has ever put in a half-ton finishes third out of four.
581,002 Silverados and 353,347 Sierras were sold in the United States in 2025 in GCBC’s series, the Sierra’s strongest year on record, and the Silverado’s total sits against a 2005 peak of 705,981. Through June 2026 the Silverado stands at 276,074, 4.6% below the 289,252 of the first half of 2025, and the Sierra at 170,754, up 0.9%; both first-half figures match GM’s own second-quarter table to the unit. That table also splits the trucks the way the new engines do: the light-duty Silverado grew 3.1% to 179,393 and the light-duty Sierra 5.1% to 118,068, while Silverado HD fell 14.4% to 89,491 and Sierra HD 8.1% to 49,642. The L76 and L78 are 1500 engines. They arrive into the half of the line that is growing, and the tow rating they carry is the number that half of the line sells on.
357,801 F-Series trucks sold in the first half by Ford’s own count, 13% below the 412,858 in GCBC’s series for the same months of 2025, which Ford attributes to a retiming of commercial production after last year’s aluminum shortages. GM’s two nameplates together sold 446,828 in the half, 89,027 more than Ford’s. The 2027 trucks and their V8s are what GM brings to a comparison Ford is, for one half-year, losing on volume.
Dealers will spend the 2027 model year explaining the table. The customer walking in for the biggest number available gets the version with the least towing capacity and the smallest payload in the V8 range, and the customer who tows for a living wants the engine one rung down. The engineering behind it is ordinary, since a heavier, higher-output engine eats into gross combined weight rating and shifts the axle math. GM has published the horsepower without an explanation of the trade, and the trailering conversation on the lot is now a conversation about why the smaller engine is the work engine.
6 millimetres of additional piston stroke is what takes the outgoing 5.3L and 6.2L to 5.7 litres and 6.6 litres, returning the 350 and 400 cubic-inch displacements to the Small Block family. Both engines get higher compression, larger throttle diameters, retuned intake manifolds and a dual-fuel system combining direct and port injection. A new lubrication system adds a continuously variable oil pump and an on-engine oil cooler. GM expects to complete more than 1.5 million miles of on-road validation before the trucks reach dealerships later this year.
The 6.2L being replaced is the L87, and NHTSA opened Engineering Analysis EA26005 on it on August 20, covering 997,743 GM vehicles from the 2021 to 2026 model years after engines that had already received the recall remedy kept failing. The affected population runs through the Silverado and Sierra 1500 and into the Tahoe, Suburban, Yukon and Escalade. GM recalled the L87, built a remedy and is cooperating with the escalated review rather than contesting its scope, which is the responsible half of this record. The open question for a fixed-ops manager is whether the continuously variable oil pump and reworked oil feed on the Gen-6 engines answer what the L87 investigation found. GM has not said.
Flint Engine Operations builds the initial L76 and L78 volume, with additional capacity planned for Tonawanda and St. Catharines. GM names $9 billion of US manufacturing investment including $888 million at Tonawanda, and C$691 million at St. Catharines Propulsion for sixth-generation V8s. The Canadian commitment was part of the GM settlement Unifor ratified in August, and it is the most concrete product mandate any Detroit Three company has attached to a Canadian plant in a month when Stellantis is trying to sell one.
September 15 brought a second reversal on the same two trucks: a GM product manager told The Verge, in remarks carried by CNBC, that Apple CarPlay and Android Auto return on the 2027 Silverado and Sierra in a split-screen layout beside GM’s own apps, for those two nameplates rather than fleet-wide. GM has not issued a release on it. If the reports hold, the company that argued its own software stack was worth the friction has restored the feature first on the two nameplates that carry its profit and, on GM’s first-half table, its growth.
9,700 is the number that should follow the 2027 trucks into every comparison until GM publishes pricing, and 179,393 light-duty Silverados in six months is the reason the number matters.
