2007-2008 GMC Sierra and Chevy Silverado (2500 & 3500) Trucks Gain 19 HP with K&N Air Intake.  The GMC Sierra 3500 is a heavy-duty pickup truck. It is almost a twin to the Chevrolet Silverado, a 1- ton workhorse that includes a stiff suspension, rugged frame and a very powerful engine. (more…)