
Every truck manufacturer has that one legendary engine. It’s a point of pride for the entire brand because it proves that all of the power, dependability, and durability is there, exactly as advertised. Every truck manufacturer has worked hard over the years to engineer a truck that hits the mark between being cool, being efficient, and being able to tow and haul massive loads. If you are looking for a used Ram diesel truck, then that engine is the Cummins.
Cummins and Ram have been almost synonymous since 1989, and in those three decades, a lot of ground has been broken and limits explored. From the first 160 horsepower efforts in 1989 to the 400 horsepower version that graces the 2021 Ram 3500, there’s a story told in torque and turbo. As you peruse the used Ram diesel options at your local dealership, you may wonder about the excitement surrounding the Cummins turbo diesel engine. To understand how this power came to be, let’s look at how it all began.
The History of Cummins
Most truck enthusiasts know the backstory on the Ram line of trucks. Launched in 1981 under the Dodge brand, Ram proved so successful that it gained independence from its parent brand in 2010. Since then, Ram has only grown in popularity, and its pickup is now the second best-selling vehicle in America Fewer drivers, however, are familiar with the story of Clessie Cummins.
Clessie Cummins had little more than an eighth-grade education and a knack for all things mechanical when he became a chauffeur for banker William Irwin of Columbus, Indiana. There are legends of a young Clessie building a steam engine water pump as a child, but the tale of the diesel engine begins in 1918. In that year, Cummins saw an imported Dutch Hvid engine and, thanks to the financial backing of Mr. Irwin, secured a contract with Hvid to license-build its engines for the American market.
Despite an initial rough start selling stationary diesel engines for agricultural use, in 1930, Cummins adapted a diesel engine to a Packard sedan and drove the vehicle to New York City, averaging an incredible (for the day) twenty-six miles per gallon. The first Cummins engine to grace a truck appeared in 1931 when a Model U engine was added to a Marion truck. Cummins took this experiment on a journey from New York City to Los Angeles, completing the voyage in 97 hours without the benefit of the United States interstate highway system we have today.
Over the coming years, Cummins would adapt diesel engines to more and more vehicles, each time impressing the public with the speed and efficiency of his engines, eventually becoming a public racetrack fixture with his unique diesel-powered race cars. In fact, the Indianapolis 500 was a coveted dream for Cummins. Though he never won this race with his vehicles, his vehicles performed well and to high praise. His first effort finished 13th in the 1931 Indy 500 without making a single pit stop. It was also the racing industry that inspired Cummins to make only four-stroke engines after a two-stroke engine competing in the 1934 Indy 500 seized up after finishing the race.

When Ram Met Cummins
In the 1980s, Dodge was truly trying to get its new truck brand off the ground, so to speak, but outdated body styles and the lack of a diesel engine was making business difficult. According to legend, the medium-duty trucks Dodge was putting on the market caught the attention of Cummins (the company – Clessie Cummins had retired back in 1955), which was trying to infiltrate the consumer truck segment in addition to the commercial truck market. The rest, as they say, was magic.
The first Cummins/Ram collaboration was a 5.9L B-series diesel engine that provided 160 horsepower and 400 lb-ft of torque after being de-tuned to fit in a consumer truck. The Ram, on the other hand, had to undergo a bevy of changes to allow the massive engine to fit, including a larger radiator and the addition of an engine cooler. While the horsepower ratings were nothing new to the medium-duty truck niche, the high torque was, and suddenly, a new American classic was born.
The second generation of Cummins Ram engines was further tweaked and tuned in 1998 to provide even more power, providing 215 horsepower and 440 lb-ft of torque. However, that was just the start. By 2002, those numbers had crept up to 245 hp and 505 lb-ft of torque in the High Output version of the 5.9L Cummins.
In 2007, the Dodge Ram (as it was named at the time) 2500 and 3500 heavy-duty pickup trucks appeared at the Washington DC Auto Show to reveal a new 6.7L Cummins turbo diesel that met tightening US emissions regulations. While the regulations had a deadline of 2010, Ram and Cummins managed to work above the curve, creating a truck that could operate with B5 and B20 biodiesel.
The secret to the new BLUETEC engine was a Bosch fuel system, a variable geometry turbocharger, and cutting edge Cummins cooled exhaust gas recirculation. To meet emissions, it also included an advanced exhaust after-treatment system that was capable of manipulating diesel output and oxidation.
Looking at the specifications of the used Ram diesel trucks on the market today, you’ll see the power numbers have climbed significantly over the years. Just a decade ago, the 2011 Ram 2500 included an optional 6.7L Cummins turbo diesel that provided 350 horsepower and 800 lb-ft of torque, proving that innovation is the key to power and performance.

The Cummins Engine We Know Today
According to Cummins, 75% of the Ram 2500 and 3500 drivers choose the Cummins turbo diesel engine over other options. Looking at the specs, it’s easy to see why. The 2021 Ram 2500, for example, offers a 6.7L Cummins turbo diesel engine that easily provides 370 horsepower and 850 lb-ft of torque. The result is a payload capacity of 3,160 pounds and a towing maximum of 19,680 pounds, making it a solid contender amongst the HD truck community.
The real record-breaker, however, is the big brother – the 2021 Ram 3500. When fitted with the available 6.7L High-Output Cummins turbo diesel engine, the 3500 can cheerfully tow over 37,000 pounds, thanks to a mind-bending 400 horsepower and 1,075 lb/ft torque.
When the Ram 3500 finally reached that magical 4-digit torque number in 2019, it was a testimony to what innovation and perseverance can create. Many felt it was a reasonable goal for Cummins and Ram to pursue together, given the enduring nature of their partnership. After all, it is the Cummins diesel engine that drives Ram heavy-duty trucks to push hard, pull harder, and take on job after job. Continuing the symbiotic relationship, it is the competitive nature and constant need for redesign, reimagination, and re-engineering within the automotive industry that has kept Cummins on the cutting edge.
There’s a reason Cummins diesel engines are a big deal amongst Ram trucks. From the used Dodge Rams seen on dealership lots to the heavy-duty Ram trucks that roll off the assembly line today, this partnership has allowed Americans to keep working hard through the years. Since 1989, this partnership has helped workers reach peak performance, thanks to a heavy-duty engine in a mighty truck.

