Vehicle Overview, , , Chevrolet's full-size pickup was redesigned for 1999, and this year's major change is the addition of four-door versions of the extended cab. , , All 1999 extended-cab Silverados and early 2000 models came with two conventional front doors and a third door on the passenger side that opens to the rear. Production of a rear-opening fourth door on the driver's side started in December, and all extended-cab models now come with four doors. , , GMC sells a corporate twin of the Silverado called the Sierra, which also gets the four-door feature for its extended-cab models. Silverado and Sierra come in 1500 (half ton) and 2500 (light-duty three-quarter ton) payload ratings. General Motors' heavy-duty three-quarter-ton and one-ton pickups are the Chevy C/K and GMC Sierra Classic, which are built from an older design. , , For the 2001 model year, both Chevy and GMC plan to introduce crew-cab models with four conventional doors that open toward the front, matching a feature already available on the rival Ford F-150., , Exterior, Silverado comes in four sizes: regular cabs and extended cabs, both with a choice of 6.5- or 8-foot cargo beds. Front styling on the Silverado matches that of the new Chevy Tahoe and Suburban sport utility vehicles, which are built from the same basic design. A Sportside cargo bed with flared rear fenders is optional, in place of the standard slab-sided cargo bed. , , The rear doors on extended-cab models cannot be opened unless the front doors are opened first, and they must be closed before the front doors are shut. , , Interior, Inside the cab, furnishings range from plain to plush. Vinyl seats are standard on base models and cloth is optional. Leather upholstery is standard on the LT trim level — the most expensive — and optional on LS models. , , Regular-cab models come with a three-place bench seat or a pair of buckets. All extended-cab models have a three-place rear bench and either a front bench that holds three or two buckets. , , Under the Hood, Four engines are available, starting with a 200-horsepower 4.3-liter V-6 that is standard in two-wheel-drive 1500 models. Most buyers choose one of the optional V-8s: a 4.8-liter with 270 horsepower or a 5.3-liter with 285 horsepower. Both V-8s have 15 horsepower more than last year's models. The 5.3-liter V-8 is standard on 2500 models and a 300-horsepower 6.0-liter V-8 is optional. , , Four-wheel drive is available across the board and two systems are offered. Insta-Trac allows shifting in and out of 4WD High while moving. Autotrac sends all the power to the rear wheels on smooth, dry pavement and automatically transfers power to the front wheels as needed on slippery surfaces., , Performance, Chevy's full-size trucks are competitive with the Ford F-Series and Dodge Ram in most key areas, though Chevy's styling is more conservative and Ford already offers crew-cab models. Chevy makes four-wheel antilock brakes standard — they are optional on the F-150 — and its extended-cab models are roomier than Ford's or Dodge's., , , Convenience Features , , Remote keyless entry , Front cupholders , Tilt steering wheel , Memory seat , Entertainment Features , , Safety and Security , , ABS brakes , Dual front impact airbags , Passenger cancellable airbag , Ignition disable , Security system , Panic alarm