GM to unveil remodeled pick-ups DETROIT General Motors (GM) is giving its pickup trucks a much-needed makeover. The company is unveiling new versions of its top-selling Chevrolet Silverado and GMC Sierra on Thursday. The 2014 models will go on sale by early spring or late summer. And they roll into a market where truck sales are growing after a five-year slump. The timing is good: GM's current models are looking dated and sales are slowing. The new Silverado and Sierra are a little sleeker than the current models. Gas mileage and prices are not being announced Thursday. The new trucks come with a choice of three revamped engines: a V-6 that can tow a substantial trailer, and two V-8s.