General Motors got the diesel truck enthusiast world’s attention earlier this week when it revealed the face of the 2017 GMC Sierra Denali 2500 HD and its prominent hood scoop. That release was vague to its function other than to say it “hints what lies beneath.” It doesn’t take a rocket scientist to deduce that an updated 6.6L Duramax V-8 diesel engine lies beneath. Thankfully, GM has given us a little more details on the scoop’s function, this time accompanied by a photo of a Silverado 2500 HD.