General Motors' redesigned high, wide and handsome full-size pickup truck -- sold as the Chevrolet Silverado and GMC Sierra -- is the most important product it sells. That's because it's the top-selling vehicle in America and generates high profits.

Last year was a bad one for big pickup trucks, but combined sales of GM's Silverado and Sierra totaled 846,805 units. (We're concentrating on the Silverado I tested in this column.)

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PHOTO GALLERY

2007 pickup trucks

2007 CHEVROLET SILVERADO 1500

PRICE: $17,860-$38,090

LIKES: New look. More power. Roomy. Fast V-8s. Comfortable front seat. Very maneuverable.

DISLIKES: Low inside door handles. Upright back seat in extended cab model. A stretch to reach some controls.

Taken individually, the highly profitable Silverado finished No. 2 last year in total industry sales behind Ford Motor's F-Series full-size pickup, with sales of 636,069 units. The more upscale Sierra found 210,736 buyers.

With those numbers and high profits, no wonder Toyota badly wants to score better in the lucrative full-size pickup market with its new Tundra, for which it has built a plant in Texas -- heart of the U.S. pickup market.

Many full-size pickups are used as cars, especially the four-door crew and extended-cab models, which have four doors and back seats.

GM thus is emphasizing the same features of its redesigned Silverado/Sierra pickup that are mentioned when discussing new autos: stiffer bodies and frames, more safety features, nicer interiors, better aerodynamics, smoother ride and higher fuel economy. (Carryover 1999-2006 models are sold as the Silverado Classic and GMC Sierra Classic.)

The more rigidly built new Silverado 1500 has smoother styling and more power. Some of its V-8s have seamless cylinder deactivation that lets you run with four cylinders under lighter loads and are E-85 capable, using a mixture of 85 percent ethanol and 15 percent gasoline. But good luck, finding an E85 filling station.

Estimated fuel economy numbers are all over the place, depending on such things as engine size and body style. It ranges from 15-17 mpg in the city to 19-21 on the highway. Not bad, considering these are big trucks, which call for extra effort to get in and out. (At least rear doors on four-door models open widely.)

The new Silverado is several inches longer and 1.5 inches wider. Besides slicker aerodynamics, it steers and handles better, thanks to such things as a new fully boxed frame, new rack-and-pinion steering and a new front suspension with "coil-over" (a major advancement) shock absorbers. Front and rear tracks also are wider for greater stability. The result is the Silverado can be maneuvered nearly like a big car, although a driver must keep the longer body in mind.

The steering is tightly responsive, as are the brakes, which have a pedal with a linear action. My test Silverado had the optional Z71 off-road suspension. It caused the ride to be firmer, but not uncomfortable. Directional stability is outstanding.

Anti-lock brakes are standard and effective, and newly offered for some models are traction/anti-skid control and curtain side air bags.

There are 40 versions of the Silverado 1500, with list prices ranging from $17,860 for a regular rear-drive two-door cab model with a 195-horsepower 4.3-liter V-6 to $38,090 for a fancy LTZ crew cab model with leather upholstery, heated front seats and rear radio controls. It has a 315-horsepower 5.3-liter V-8 with four-wheel drive and four doors that open individually.

In between regular and crew cab models are extended-cab versions, which require that rear doors be closed before front ones can be shut. Also, the back-seat area in my extended cab test Silverado was tight and the seat was too upright for much comfort. Those who want a more comfortable back seat should opt for the crew cab version.

Two four-wheel-drive systems with low-range gearing for off-road use are offered. One system shouldn't be engaged on dry roads, the other can be. Designs for the quiet, comfortable interior are functional, with such things as easily read gauges. Outside door handles are large, but inside door handles are too low.

Most controls are easy to use, but some are placed just out of normal reach. For more interior room, the rear seat cushion folds against the seatback, providing a large, flat-floor cargo area.

There also are several bed lengths. Regulars have 6.5- to 8.1-foot bed lengths. Crews have a 5.8-foot bed length, and Extendeds are offered in all three bed lengths. A $95 EZ Lift tailgate package contains a light, locking tailgate that easily opens and closes. Over the long run, you'll bless this option.

The V-8s produce 295, 315 and 367 horsepower and strong acceleration. They also provide plenty of torque, and towing heavy objects is no problem. My test $25,960 Silverado 1500 extended cab rear-drive model with the 295-horsepower V-8 was quite fast, with quick 65-75 mph passing times.

You can get a $685-$795 power sunroof. A key option is a $715 Safety Package. It has power adjustable pedals for shorter drivers, curtain side air bags and rear-obstacle detection system, but it isn't available for regular cab models.

Keeping up with all this? You probably are if you're a veteran full-size pickup truck owner. If so, you know things can get a lot more complicated when such things as option packages containing numerous features are considered.

One fact that should be easily understood by everyone is that a manual gearbox no longer is offered for the Silverado -- it now only comes with a four-speed automatic transmission. Toyota's Tundra offers five- and six-speed automatics (but no manual gearbox). Ford's F-150 has a four-speed automatic, with a manual still offered. However, the Silverado transmission shifts smoothly and provides quick downshifts.

The large pickup market is the last lucrative Detroit stronghold, but domestic pickups such as the Silverado should more than hold their own in it.