The battle in six-cylinder pickups takes an interesting twist this fall with the launch of the 2014 Ford F-150 Tremor (built for speed) and the 2014 Ram 1500 EcoDiesel (built for high mileage and heavy loads).

Both trucks feature turbocharged V6 engines, but take different approaches to reach different segments of the full-size pickup audience.

The new Ford and Ram entries - one built for speed, the other for high mileage and heavy loads - are hitting the US market as General Motors Co's recently redesigned 2014 Chevrolet Silverado and GMC Sierra pickups are beginning to reach U.S. dealers in significant numbers.

Chrysler Group LLC hopes to divert some attention from the new GM trucks with its new 2014 Ram 1500 EcoDiesel, the industry's first light-duty V6 diesel pickup.

Ford Motor Co is counterpunching with the 2014 Tremor, the industry's quickest and most powerful six-cylinder pickup.

The Ram 1500 EcoDiesel features a 3.0-liter turbocharged V6 diesel from Italy's VM Motori, a longtime supplier to Chrysler and an affiliate of the US automaker's corporate parent Fiat SpA.

Fitted with an eight-speed automatic transmission, the EcoDiesel delivers 240 horsepower and 420 pounds-feet of torque. Chrysler said the diesel version of the Ram 1500 will deliver better than 25 miles per gallon in highway driving.

Ford's Tremor, a short-wheelbase version of the regular-cab F-150, gets the company's 3.5-liter EcoBoost engine, a turbocharged, direct-injection gasoline V6 rated at 365 horsepower and 420 pounds-feet.

A special "performance" axle helps the Tremor accelerate from zero to 60 miles per hour in about 6.5 seconds. EPA highway fuel economy is 22 miles per gallon.

In comparison, GM's 2014 Silverado and Sierra get a standard 4.3-liter gasoline V6 that makes 285 horsepower and 305 pounds-feet, and has an EPA highway rating of 24 mpg.

The 2014 Ram 1500 with a standard 3.6-liter V6 gasoline engine will have a base price of $25,295, and the "EcoDiesel" option will be $2,850 more, Chrysler said Friday at the trucks' introduction.

Ford has not released prices on the 2014 F-150 trucks, but said Thursday the Tremor would be more expensive than the standard F-150 V6 model.

Chevrolet has not priced the regular-cab 2014 Silverado V6, which goes on sale later this summer.

The three Detroit-based automakers dominate the full-size pickup truck market, which continues to heat up and is easily outpacing sales for cars, crossovers and SUVs. While total U.S. industry sales were up 7.3 percent through May, sales of big trucks jumped 21.2 percent.

At all three of those automakers, the light-duty pickup trucks are the company's best sellers.

In May, sales of the Ford F-Series rose 31 percent, Chevrolet Silverado sales rose 25 percent and Chrysler's Ram truck sales rose 22 per cent.-Reuters