Vortec 5.3L V8 SFI FlexFuel, 4-Speed Automatic with Overdrive, 4WD, and Cloth. STOP! Read this! Wow! Where do I start?! Don't miss out on purchasing this good-looking 2007 GMC Sierra 1500. J.D. Power and Associates gave the 2007 Sierra 1500 4.5 out of 5 Power Circles for Overall Initial Quality Design. This Sierra SLE1 is still a pretty special truck, showing off the superior ride and handling that have earned it accolades from pretty much every reviewer who got behind the wheel. The drivability is good enough to be a capable commuting vehicle for someone who wants a pickup on the weekend for hauling toys or projects.