2024 6.6 Duramax Engine Specs. The new l5p is the most capable duramax thus far offering 445 horsepower. Detailed specs and features for the 2024 gmc sierra 2500hd diesel denali ultimate including dimensions, horsepower, engine, capacity, fuel economy, transmission, engine type, cylinders,.

With this inside look, gale finds upgrades to the 2024 gen 2 engine that you won’t see on a spec sheet,. Let’s dig down to see what has been done to improve the duramax.