It’s time to finally drive the all-new 2027 Chevy Silverado HD 8.3L Duramax turbo-diesel. How does the new 555 hp L6P Mongoose V8 accelerate with a maximum trailer (38,000 lbs) trailer at the drag strip? How does the new diesel compare to the new 6.6L gas V8 when towing toy hauler camping trailers in the mountains above Tucson, Arizona? Should you buy gas or diesel? I have all this and more. Let’s dig in!
GM has redesigned or updated both heavy-duty engines. They updated the chassis, suspension, steering, and the braking system to make these trucks more capable and easier than ever to drive. Chevrolet did not change the exterior and the interior styling and design, the look remains the same for the 2027 model year.
6.6L Gas V8
This gasoline-burning engine is still focused on heavy-duty work. It’s an iron block, but it gets a new intake manifold and several other updates. The result is a bit more horsepower and class-leading torque.
| Engine | Power | Torque | |
| Chevy Silverado HD | 6.6L V8 L8S | 412 hp @ 5,200 | 472 lb-ft @ 4,000 |
| Ford Super Duty | 7.3L V8 Godzilla | 420 hp @ 5,350 | 445 lb-ft @ 4,250 |
| Ram HD | 6.4L V8 HEMI | 405 hp @ 5,600 | 429 lb-ft @ 4,000 |
The 6.6L V8 engine does not have cylinder deactivation, and it does not have Auto Start/Stop. It is still mated to a 10-speed Allison-branded automatic transmission. This is the base powertrain for GM’s 2027 heavy-duty pickup trucks.
8.3L Duramax V8 Turbo Diesel
This is an all-new engine. It’s a first production factory engine with displacement of over 500 cubic inches. It’s the new class leader in horsepower and torque. Take a look.
| Engine | Horsepower @ RPM | Torque @ RPM | |
| Chevy Silverado HD | 8.3L Duramax V8 | 555 hp @2,500 rpm | 1,230 lb-ft @1,400 rpm |
| Ford Super Duty | 6.7L HO Power Stroke V8 | 500 hp @2,600 rpm | 1,200 lb-ft @1,600 rpm |
| Ram HD | 6.7L HO Cummins I6 | 430 hp @2,800 rpm | 1,075 lb-ft @1,800 rpm |
The new Duramax is effortless to drive. The engine emits a familiar Duramax V8 turbo-diesel sound. It’s about as quiet or as loud as the outgoing L5P 6.6L Duramax V8. When towing 10,000 lbs with the new 2027 Silverado HD 3500, it feels like there is nothing behind this truck.
The new and segment exclusive EPS rack-and-pinion steering is effortless to operate. The new electric power steering feels easy and consistent at any speed and at any load.
What about the maximum towing rating? The 2027 Silverado HD is rated at a maximum rating of 38,000 lbs with an NHT max-tow diesel dually configuration. I got to drive this truck with a nearly maximum load trailer on a 1/4-mile drag strip to see if we can hit 60 MPH in the quarter mile with such a heavy trailer.
Spoiler Alert! Yes, We were able to reach 60 MPH in about 27.76 seconds with a gross combined weight of just over 45,000 lbs. The maximum GCWR on this truck is 46,500 lbs.
The NHT max-tow consideration is a two-door regular cab Silverado HD 3500 2WD dually with the new 8.3L diesel in a Work Truck trim with aluminum wheels and bed liner delete. This is a very specific configuration. Most new crew cab turbo-diesel dually Silverado HD trucks are rated to tow over 30,000 lbs.
Please join me in the video below for all the details.
