The all-new Duramax 6.6-liter diesel engine should be displayed at the Guggenheim. It's power and art; it's form and function. It's a masterpiece in every sense of the word. It's also the centerpiece of the new heavy-duty pickups offered by General Motors Co. -- under the hoods of the 2011 Chevrolet Silverados and GMC Sierras HDs. These pickups, which range in size from a basic 2500 HD work truck to a Crew Cab 3500 HD dually, may look similar to the 2010 models, but you can't judge a truck by its sheet metal.

The massive front end and those bubbly fenders, which almost grotesquely flare out and remind me of Schwarzenegger in the '70s, suggest these trucks' power; you'll have to sit behind the driver's seat to experience it. (There were a few other cosmetic changes, such as the new louvered hood, a big bumper, grille and big 20-inch wheels.)

But how much do looks matter? In today's self-absorbed world of tell me, don't show me, the Silverado and Sierra HDs quietly deliver the goods -- up to 21,700 pounds at a time.

For car people, these numbers approach the ridiculous. It's like the proverbial ant holding the Empire State Building over his head. These heavy-duty trucks can haul more than three times their own weight -- which would be the equivalent of building a 3,400-pound Chevy Malibu that tows 12,000 pounds. Of course, these heavy-duty trucks can almost carry the weight of two Malibus in their bed -- with a maximum payload capacity of 6,635 pounds.

More importantly, these trucks do so with ease.

During recent testing at GM's fabled Milford Proving Grounds, I hauled 12,000-pound trailers up a 7.2-degree grade with never a flinch. In less than a half mile up the hill, I was close to 60 mph.

None of this should come as a surprise. The new Duramax pushes out 397 horsepower and 765 pound-feet of torque. That last number in particular is simply incredible.

Let's not forget about the 6-liter V-8 gasoline engine that some owners choose over diesel, which costs $8,300 more. This V-8 still cranks out 360 horsepower and 380 pound-feet of torque. It can still tow up to 14,700 pounds -- though that depends upon the truck's configuration.

That's one best part of these big trucks. There are so many different ways to build these trucks out. Want just a gasoline work 2500HD truck with a 6-foot-5 bed? There's a version of it. Want an extended cab diesel? There's one available. And, if you want to check about every box on the order form, there's a Crew Cab, 4x4, diesel with a 8-foot-1 bed; well, that's available too. GM is like that bad battery commercial on the radio, "Yep, got that."
Surprisingly quiet ride

My test vehicles included both a Silverado 2500HD work truck with the 6-liter V-8 and a Sierra 3500HD Crew Cab dually diesel. Both were excellent on the road. Their rides were surprisingly quiet, especially the diesel, which still sounds like a big rig from the outside, but in the cabin was quite civil. There was also very little black smoke jumping out of the exhaust.

During the hill testing at Milford, that was one of the biggest surprises. The 6.6-liter uses an after-treatment injection system to make the exhaust cleaner, if there can be such a thing, The diesel exhaust fluid must be refilled about every 5,000 miles -- and if drivers don't, the truck will begin to limit performance. Overall, GM says nitrogen oxide emissions are 63 percent lower than 2010 models.

Another feature on the diesel engine is the new exhaust brake, which uses the turbos to help slow it down. The brake was extremely quiet and kept the heavy-duty trucks on a nice downhill glide path. It was almost too quiet; I wasn't always sure when it was kicking on.

Both test vehicles provided extremely smooth rides. Even the big dually was easy to handle on the open road. The asymmetrical rear leaf springs helped keep the ride jarring free, even with the bed empty.

You can also go a long way with these vehicles with the new 36-gallon tank. The diesel can also run on B20 biodiesel. While the EPA does not require mileage testing for heavy-duty trucks, GM says you can get up to 680 miles on a single tank. That puts the diesel at almost 19 mpg on the highway. That's simply incredible.

I would be remiss not to mention the all new frame and underpinnings on the Silverado HD and GMC HD. They are the HD's backbone.

The fully boxed, high-strength steel frame is crucial in increasing the HD's capabilities.

The body is 125 percent stiffer in the front and torsional stiffness has increased five times. All of that means is it won't twist and turn nearly as easy as it might in the past, which wasn't that much either.

For snow plowers, these HDs also feature a 25 percent increase in front axle weight rating to 6,000 pounds. That means any configuration truck can have a plow on it.

Inside a bit dated

For many truckers, I could end right here. The performance and frame are drastically improved on a good truck.

But for the slightly spoiled trucker, the interior remains pretty much the same as the 2010 models. It's nice, but still plain. It was last overhauled in 2007 and feels like it.

Of course, GM has ensured it comes complete with a lot of features, such as Bluetooth hands-free phone connectivity, as well as the ability to connect your iPod to the stereo system through a USB port. The optional navigation system works very well.

But this truck, inside the comfortable cabin, feels dated next to its competitors, the Heavy Duty Dodge Ram and Ford Super Duty.

The pickup wars we've seen in recent years only means trucks are getting better and better as each manufacturer raises the bar a little higher.

The Duramax, for a few months, was the most powerful diesel in the heavy-duty truck business. This week Ford Motor Co. upped the ante and raised the power on its heavy-duty diesel to stole the best in class power rating.

Super Duty owners should send a thank you note to GM because if this Duramax had not arrived, they would not have seen their trucks jump in power so soon. (Ford says otherwise and it was always in the plan.)

But something tells me this battle isn't over.

Every artist feeds off his contemporaries, his competition. The heavy-duty engineers and designers may never view their craft at a museum, but they can rest assured, the people who built the gallery, the food court and just about everything else that needs a roof probably had a heavy-duty truck in their driveway. So put that in your museum and show it.

sburgess@detnews.com (313) 223-3217

Report Card

Overall: *** 1/2

Exterior: Excellent. Refreshed to look bigger and bolder; keeps its GM looks.

Interior: Good. Well laid out but starting to look dated when compared with the competition.

Performance: Excellent. Monster capabilities with great power, smooth acceleration and on-road manners.

Pros: Lots of capabilities and different configurations.

Cons: Too much truck for some people.

Grading Scale

**** Excellent *** Good ** Fair * Poor