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Cummins swore by diesel. For decades, its B-series engines were synonymous with bulletproof turbo-diesel power. But now? Cummins just rolled out a 6.7-liter, turbocharged gasoline I6 with more torque than any pre-2004 diesel and zero emissions nonsense. Why? Because gasoline technology is improving while regulators are “legislating the diesel engine to death.” Did Cummins cave? Or did it just give truck buyers exactly what they’ve been asking for?

For years, Cummins fans have wondered what a gasoline version of the legendary 6BT would look like. The original 5.9-liter I6, introduced in 1989, earned a reputation for durability and torque. It powered everything from Ram trucks to tractors, outlasting many of the vehicles it was installed in. Now, the B6.7 Octane answers the question: what if Cummins built a gas-powered B-series? The answer? A turbocharged, 6.7-liter I6 with up to 300 horsepower and 660 lb-ft of torque—more than any diesel 6BT before 2004.

A gasoline engine with Cummins durability

This isn’t just any gasoline engine. Cummins says it was “designed specifically with durability and reliability in mind.” Built on the legendary B-series platform, it offers “diesel-like performance” but runs on standard 87-octane gasoline. That means no diesel emissions systems—no DEF, no active regenerations, no complex aftertreatment. Cummins claims it also delivers “up to 10% better fuel economy over other gasoline-powered engines depending on duty cycle.”

The timing is interesting. Ram just rolled out the Hurricane—a high-torque, turbocharged gasoline I6—and proved that truck buyers will pay for an efficient, high-power inline-six. Now Cummins is offering its own high-output, gas-powered alternative. Unlike the Hurricane, this isn’t a replacement for a V8—it’s a replacement for a diesel.

So is this the future? Maybe, but not necessarily for the right reasons. As I previously wrote in “We May Need to Relax Diesel Emissions to Save the Environment,” the push to reduce NOx emissions has made diesel engines less efficient. Stricter rules mean lower fuel economy and increased costs, even in rural areas where NOx isn’t a major problem. In the rush to eliminate diesel, regulators may be pushing truck buyers toward gasoline engines that burn more fuel overall.

That’s what makes the B6.7 Octane so compelling. It’s simple, durable, and built for high torque—exactly what Cummins fans want. It might not match a diesel 6BT’s legendary MPG, but it doesn’t have to. For truck buyers sick of emissions headaches, this might be the next best thing.

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Staff Writer

Henry Cesari

Henry Cesari is a MotorBiscuit Staff Writer who brings his deep interest in vintage cars, trucks, and motorcycles to the site. Having restored his first classic car at just 16 years old, Henry has wrenched on everything from overland campers to Japanese motorcycles and even pre-war Bugattis. Henry is also an avid attendee at local car shows and genuinely enjoys connecting with fellow auto enthusiasts. Henry earned a Bachelor’s in Anthropology and English from the University of Vermont. While Henry is interested in vintage cars, he believes the golden age of cars is yet to come. He is confident journalists will play an important role in this revolution by exposing the industry as it is now and envisioning its possible future.