The 2023 Chevy Silverado HD Duramax and 2023 GMC Sierra HD Duramax are set to receive engine updates with a boost in power. Now, one rumor has the total output from the upgraded diesel powerplants at nearly 1,100 pound-feet of torque, along with more than 500 horsepower.
Back in May, GM Authority was the first to report that the 6.6L V8 L5P turbodiesel Duramax engine equipped by the 2021 Chevy Silverado HD and 2021 GMC Sierra HD was due for an update, likely introduced in conjunction with the heavy-duty pickups’ full model refresh / mid-cycle enhancement. The new powertrain update could send final output numbers as high as 1,085 pound-feet of torque and 505 horsepower, according to a recent report from TFL Truck.
That’s a significant boost over the current 6.6L V8 L5P turbodiesel Duramax power and torque figures, rated at 910 pound-feet of torque at 1,600 rpm, and 445 horsepower at 2,800 rpm. That means the new rumored figures represent increases of 175 pound-feet and 60 horsepower.
As a reminder, the 2021 Chevy Silverado HD and 2021 GMC Sierra HD are also offered with the naturally aspirated 6.6L L8T gasoline engine, rated at 401 horsepower at 5,200 rpm and 464 pound-feet of torque at 4,000 rpm. The gasoline engine connects to a six-speed automatic, while the diesel connects to an Allison-branded 10-speed automatic.
Per the original GM Authority report made in May, it’s expected that both gasoline-powered HD models and diesel-powered HD models are in store for updates with the upcoming full model refresh. However, when those updates will be applied is still somewhat uncertain.
When GM Authority first reported on the powertrain updates, the refreshed models were expected to arrive with the 2023 model year. However, as a result of numerous delays and setbacks, including the COVID-19 pandemic and ongoing global microchip shortage, it’s possible the refreshed Chevy Silverado HD and GMC Sierra HD will not arrive until the 2024 model year.
|Vehicle||Engine||Fuel Type||Aspiration||Valvetrain||Horsepower (hp @ rpm)||Torque (lb-ft @ rpm)|
|2021 Chevy Silverado HD||6.6L L8T V8||Gasoline||Atmospheric||OHV 16-valve||401 @ 5,200||464 @ 4,000|
|2021 Chevy Silverado HD||6.6L Duramax L5P V8||Diesel||Turbocharged||OHV 32-valve||445 @ 2,800||910 @ 1,600|
|2021 Ford Super Duty||6.2L Boss V8||Gasoline||Atmospheric||SOHC 16-valve||385 @ 5,750||430 @ 3,800|
|2021 Ford Super Duty||7.3L Godzilla V8||Gasoline||Atmospheric||OHV 16-valve||430 @ 5,500||475 @ 4,000|
|2021 Ford Super Duty||6.7L Power Stroke Scorpion V8||Diesel||Turbocharged||DOHC 32-valve||475 @ 2,800||1,050 @ 1,600|
|2021 GMC Sierra HD||6.6L L8T V8||Gasoline||Atmospheric||OHV 16-valve||401 @ 5,200||464 @ 4,000|
|2021 GMC Sierra HD||6.6L Duramax L5P V8||Diesel||Turbocharged||OHV 32-valve||445 @ 2,800||910 @ 1,600|
|2021 Ram HD||6.4L HEMI V8||Gasoline||Atmospheric||OHV 16-valve||410 @ 5,600||429 @ 4,000|
|2021 Ram HD||6.7L Cummins I6||Diesel||Turbocharged||OHV 24-valve||370 @ 2,800||850 @ 1,700|
|2021 Ram HD||6.7L Cummins I6 HO||Diesel||Turbocharged||OHV 24-valve||420 @ 2,800||1,075 @ 1,800|