GM is tight-lipped about it's new Chevy Silverado pick up set to begin production in Flint.

All GM spokesman Tom Wickham will say is "we're going to build it".

But the website "Digital Trends" says limited production is already underway in Flint on Van Slyke Road for the 2014 Chevy Silverado and GMC Sierra. Wickham admits "it's a secret we're sitting on". But the company has released a spy photo of the truck.

The website says the truck is being tested in Mesa Arizona right now, with full scale production expected to ramp up next year. Consumers shouldn't expect to see any radical changes, although one of the versions is expected to include what's called GM's small block V-8. The new Silverado/Sierra is expected to have better fuel economy and more power. It will also be lighter than the current version, using more aluminum in its body.

It will compete with the number 1 vehicle sold in the U-S, the Ford F-150 pick up. Also in its crosshairs: the Dodge 1500 from Chrysler. Both of those trucks feature newly restyled models, unlike the Silverado/Sierra, which hasn't received an update since 2007.

Industry experts say GM has to hit a home run with the new Silverado/Sierra, to remain competitive in the truck market.

For the full story click here : http://www.digitaltrends.com/cars/gm-teases-2014-chevrolet-silverado-with-camouflaged-prototypes/

For a Car and Driver story click here: http://www.caranddriver.com/news/2014-chevrolet-silverado-gmc-sierra-spy-photos-future-cars

For GM information on the current truck: http://www.chevrolet.com/silverado-pickup-trucks.