DETROIT – When the all-new 2014 GMC Sierra full-size pickup arrives this summer, its standard 4.3L EcoTec V-6 it will offer the most torque of any standard V-6 in the segment – 305 lb-ft (413 Nm).

Buyers will choose from three new, advanced EcoTec3 engines – a 5.3L available at launch, followed by the 4.3L and 6.2L versions available later this year. All are designed specifically for the high trailering and hauling demands unique to truck buyers.

Torque is the turning force that generates off-the-line acceleration and confident trailering performance. Sierras equipped with the 4.3L EcoTec3 V-6 will have trailering ratings up to 7,200 pounds (3,266 kg) for a regular cab, short bed, four-wheel-drive model – 500 pounds more than the most capable Ford F-150 3.7L and 700 pounds more than a Ram 1500 3.6L. Sierra’s standard V-6 produces an SAE-certified 285 horsepower (212 kW) and is matched with a proven, efficient six-speed automatic transmission. EPA fuel economy estimates will be released later.

Like Sierra’s optional 5.3L and 6.2L EcoTec3 V-8 engines, the new V-6 features three state-of-the-art technologies – direct injection, active fuel management (cylinder deactivation) and continuously variable valve timing – that have been proven and perfected through 6 million hours of computational analysis by engineers studying the combustion process. In all, 10 million CPU hours were spent refining and making the most of the Sierra’s EcoTec3 engines.

“This is technology no other truck maker can match, and we offer it in every EcoTec3 engines, for every customer,” said Jordan Lee, GM Powertrain chief engineer. “It is a standard feature, so our drivers get our best and most sophisticated technology regardless of trim level.”

Although they share only a handful of parts with previous Sierra engines, the new EcoTec3 V-6 builds on experience gained from millions of trucks and billions of real-world customer miles resulting from a half-century of leadership in V-6 engine development. In 1960, GMC debuted the first V-6 pickup truck ever and offered it exclusively through most of the ’60s.

That engine, offered in various displacements starting at 5.0L, was designed with aluminum pistons, improved cooling and a stout crankshaft and bearings designed for unprecedented durability.

“The family of V-6 engines introduced in 1960 was designed to last, and I’ve heard of some owners going more than 450,000 miles on the original engine,” said Donald Meyer, GMC truck historian. “They had really high torque and pulled loads well. GMC engineers know how to build durable, reliable engines that never quit.”

Like the 2014 engine, the 4.3L V-6 introduced as standard equipment for GMC half-ton pickups in 1985 used geometry and engineering from the brand’s proven Small Block V-8. As with today’s V-6, engineers studied the combustion chamber, developing “Vortec” technology that swirled the air and fuel inside the engine to create a more homogenous mix, improving power and efficiency. That engine was the basis for new generations of engines through the 2013 model year.

The 4.3 will have a fat torque curve that the LFX won't be able to touch.

The LFX is also a DOHC set up instead of CiB.