Chevy hasn't been saying so publicly, but it's been a little worried about the fact Ram has taken its place as number two truck maker in the USA. And it's not just the fact that Ram is selling more pickups than the Bowtie-branded truck maker is, Chevy's sales are estimated to be down, too, by 12% through May compared to the same time a year ago.

But numbers like these don't tell the whole story. Looking at the fact Chevy recently made sizable investments into two of its truck plants, $24 million for its Fort Wayne, Indiana plant so it can build more Silverado and Sierra 1500s and a $150 million cash infusion into its Flint Assembly facility where Silverado and Sierra HDs are made, it's easy to see that the automaker sees strong sales on the horizon.

And in order to usher in the glory days, Chevy made sure to cut the new Silverado HD's price so that the truck is actually cheaper than the vehicle it replaces. But that's not all. According to what Tim Herrick, executive chief engineer of GM's full-size trucks told Automotive News, the new Silverado and Sierra have a secret weapon that will help reclaim Chevy's crown over Ram.

Surprisingly, the Silverado and Sierra's advantage is fuel economy. It's not the first thing one expects truck buyers to care about, but Ford proved that isn't the case when it started offering turbocharged EcoBoost engines in the F-150. The main engine in question is Chevy's 3.0-liter inline-six Duramax diesel, which is a direct contender to Ford's 3.0-liter turbocharged V6 Power Stroke diesel offered in the F-150.

That engine enables the F-150 to achieve over 30 mpg on the freeway given the proper drivetrain setup, but GM's own internal testing (EPA ratings have yet to be revealed) has found that its six-cylinder diesel can reach numbers as high as 30-40 mpg at speeds of 50-65 mph. "We're just in the final certification for this," said Herrick. "This will be a number that's extremely impressive."

Given that GM's diesel, which will come mated to a ten-speed automatic, makes 277 horsepower and 460 pound-feet of torque, it will outdo Ford's 3.0-liter Power Stroke, which makes 250 hp and 440 pound-feet of torque, and Ram's upcoming EcoDiesel engine, which will make about 260 horsepower. Seems like the pickup truck race is just starting to get hot.