GMC Sierra All Terrain HD Concept is ready to play dirty

Cars are cool, but we certainly love ourselves some big, bad, hardcore pickups – you know, like the ford f 150 svt raptor. General Motors’ conceptual answer to Ford‘s desert-blasting pickup is this, the Sierra All Terrain HD concept, which we’ll be seeing for the first time at the Detroit auto show next week.GMC’s brutish pickup relies on The General’s 6.6-liter Duramax diesel V8 for power – 397