GM debuts in-house Duramax 8.3L V8 and new control tech for 2027 Silverado and Sierra HDs

General Motors revealed major updates for the 2027 Chevrolet Silverado HD and GMC Sierra HD lineups centered on an all-new Duramax 8.3L Turbo‑Diesel V8. The engine, GM’s first ground-up in-house heavy‑duty diesel V8 for pickup applications, is rated at 555 horsepower and 1,230 lb-ft of torque, and will be offered as an available option.

Alongside the diesel, GM is introducing segment-first rack‑and‑pinion electric power steering for its HD trucks and a new electronic brake‑boost system. The package of mechanical and electronic upgrades is paired with a maximum available conventional trailering capacity up to 20,000 pounds and gooseneck capability up to 38,000 pounds on properly equipped models, and an enhanced 6.6L gas V8 now rated at 412 horsepower and 472 lb-ft.

For Michigan enthusiasts and commercial operators, the combination of a high‑torque in‑house diesel, improved steering feel, and electronic braking could change expectations for towing control and drivability in work trucks. GM says the 2027 Silverado HD and Sierra HD are expected to reach U.S. dealers beginning late 2026; GM-provided figures and availability will determine how these trucks fit local towing and fleet needs.