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Although small diesel car engines failed in America, massive diesel power plants are still desirable in heavy-duty pickup trucks. The rumor mill is abuzz with the possibility that GM could bring a massive 8.3-liter Duramax diesel V8 engine to the market. In a world where most automakers are ditching displacement, GM could bring back the timeless adage that “there’s no replacement for displacement.”

Heavy-duty trucks still use massive engines

The Detroit Big Three continue delivering big trucks with big engines. Whether fueled by gas or diesel, Ford, GM, and Ram, all deliver impressive power figures with massive engines in large trucks. Once you reach the three-quarter-ton or larger pickups, the power and towing figures hit insane levels.

Currently, 40,000 pounds is the top towing figure offered in the heavy-duty pickup truck market. This new Duramax could achieve a much higher rating, but it might not arrive for a few years or actually be real.

An 8.3-liter Duramax diesel engine is still just a rumor

So far, General Motors hasn’t confirmed this new engine’s development. The team at The Fast Lane Truck received unconfirmed information regarding this new engine. Although the half-ton truck and smaller vehicle market continues to transition to eco-friendly, smaller-displacement powertrains, diesel-powered trucks have become more powerful.

The rumor mill indicates a new 8.3-liter Duramax turbodiesel V8 engine could deliver 600 horsepower and 1,200 lb-ft of torque. This would be a higher power level than today’s top diesel engine.

What’s the most powerful heavy-duty truck available now?

The Ford F-450 Super Duty truck can tow up to 40,000 pounds. Only the Regular Cab model with the two-wheel drive system can hit this figure. Of course, the 6.7-liter Power Stroke diesel engine and Max Tow package must also be part of the package for this truck to tow this incredible figure.

The GM heavy-duty truck lineup only reaches 36,000 pounds of towing. The Chevy Silverado 3500hD/GMC Sierra 3500HD with the Duramax diesel engine reaches this tow rating.

2024 Chevrolet Silverado 3500HD Dually heavy-duty truck with a Duramax diesel engine at a job site.
2024 Chevrolet Silverado 3500HD Dually | Chevroleet

Could a larger engine deliver a better emissions rating than current engines?

There’s the potential for a larger displacement diesel engine to produce fewer NOx emissions. The 8.3 liters of displacement could enable the engine to utilize lower cylinder pressures and temperatures, which also means a lower compression ratio. While this is a potential result, other challenges could keep this large displacement engine from becoming a reality.

Will the current transmission handle the power?

If GM produces a new 8.3-liter Duramax engine, the current Allison 10-speed automatic transmission might not be strong enough to handle the power. Part of the development process would be creating a transmission that works seamlessly with this big engine. This should deliver a powertrain that can best the Ford with more than 40,000 pounds of towing capacity.

Learn more about the rumors of this GM engine from the TFL Trucks team in the video below: