Vortec 5.3L V8 SFI and 4-Speed Automatic with Overdrive. A real lug bug. These measurements mean business. Go ahead, tretch out. Prices do not include dealer installed options. Are you interested in a simply outstanding truck? Then take a look at this wonderful-looking 2006 GMC Sierra 1500. It is nicely equipped with features such as 4-Speed Automatic with Overdrive and Vortec 5.3L V8 SFI. J.D. Power named the 2006 Sierra 1500 as the highest ranked in Overall Initial Quality Design in its class. This GMC Sierra 1500 has a great cockpit layout, ith all the controls easy to find and right where you need them.