Chevrolet will take the wraps off of its new 2014 Silverado Dec. 13 at a special event in Detroit.

The fullsize Silverado pickup has wilted on the vine compared to its top competitors the Ford F-150 and Ram 1500. Both of those pickups have undergone extensive makeovers and upgrades, while the Silverado and its sibling, the GMC Sierra, have remained relatively untouched for seven years.

Perhaps that's one reason Silverado sales have remained flat this year – up a mere .2 percent – while Ford F-Series have jumped 10.9 percent and Ram sales have spiked 19.5 percent through September.

The Silverado has always closely followed the F-150 in total sales, but this year the F-150 has created some separation. Through September, Ford has sold 463,733 pickups, while Chevrolet has sold 298,200 pickups. Toyota has sold more Camrys this year than Chevy has pickups, something that rarely happens.

But GM hopes to see a big change next year when it rolls out the new Silverado. (The public will get its first chance to see the new Silverado in person at the Detroit Auto Show in January.)

However, Ram and Ford have raised the bar significantly. Ford has found success in its EcoBoost powered F-150, capitalizing on it's 3.5-liter twin turbo V6 that replaces bigger and less efficient V8s. More than half of Ford's F-150 sales have been V6 models. Furthermore, Ram has rolled out a V6 Ram with an eight-speed automatic transmission that can hit 25 mpg on the highway, taking the fuel economy title from Ford. Chevy will need to set new high marks if it wants to win over new customers.

Rumors have swirled around the new Silverado, including one that Chevy will include a turbocharged V6 to compete with the Ford's EcoBoost. Chevrolet executives have declined to comment.

Last week, Chevrolet debuted it's fifth generation Small Block Engine that will be under the hood of many pickups.

That 450-horsepower V8 promises fuel efficiency and power, though it's not likely beat the Ram's V6. The 6.2-liter engine does arrive with lots of high tech features ranging from shutting off four cylinders when not needed to a direct injection system that promises to burn fuel more efficiently.

Recent spy photos of the Silverado – one was released by Chevy – suggest the body may not have changed significantly, but no one has seen inside the Silverado yet. That's where Chevy will have a shot to wow customers with a new telematics system, better seats and other features. For pickup buyers, it's the little features that can make a big difference and ultimately sway them one way or another.

We'll find out more in December. In the meantime, check out spy photos of the Silverado on Autoblog.