Sold as only an Extended Cab version in 1999, the GMC Sierra Classic 1500 pickup truck is offered in SLE and SLT trim levels with a Wideside bed box. New for 1999, the outside of the 1999 GMC Sierra 1500, additional paint colors are presented. Easier access to the rear seat is provided thanks to a third door on the passenger side made standard on all Sierra Classic 1500 Extended Cab models. Well-equipped for a full-size truck, cruise control, air conditioning, tilt steering wheel and power windows are found on all 1999 GMC Sierra Classic 1500 models as standard. Rear wheel and four-wheel drivetrain models continue to be offered on the 1999 GMC Sierra Classic 1500. Without a V-6 powerplant option, the 1999 GMC Sierra Classic 1500 model comes with a standard 5-liter Vortec V-8 engine producing 230 horsepower along with delivering 285 pounds-feet of torque. For a more aggressive 255 horsepower, the 1999 GMC Sierra Classic 1500 comes with a 5.7 liter V-8 Vortec model. On all Sierra Classic 1500 models in 1999 are mated a four-speed automatic transmission as standard equipment. For safety, four-wheel anti-lock braking and dual airbags are GMC Sierra Classic 1500 standard features.