During NTEA Work Truck Week 2025, Kenworth showed the Cummins B6.7 Octane engine for the first time. The new gasoline engine will be EPA 2027 certified, will meet strict CARB low NOx regulations, and will be available for order later this year in Kenworth’s line of Class 5-7 conventional medium-duty trucks.
The Cummins gasoline engine provides diesel-like performance, with horsepower ranging from 200 to 300 horsepower and up to 660 lb.-ft. of torque, paired with the Paccar TX-8 automated transmission.
Cummins said the engine is 10% more fuel efficient than other gasoline engines in its category, and it has an extended oil drain interval of up to 15,000 miles.
“The engine was validated against the same standards as Cummins diesel B6.7 engine,” said Kevin Haygood, Kenworth’s assistant sales and marketing manager. “With environmental regulations changing, it spurred us to offer another engine option to our customers. The new Cummins B6.7 Octane engine will meet stringent emission regulations, so we expect it to be a popular option in California and other states that have adopted CARB’s standards.”
Haygood said the new engine could be a great fit for many of Kenworth’s customers and their applications, especially in P&D and towing applications.
“We also see it being popular for the lease and rental markets, as well as for landscapers, where those behind the wheel are used to driving gas-powered vehicles,” he said.
Simplified Engine Maintenance
According to Haygood, the B6.7 Octane engine simplifies maintenance.
“There is no need for DEF and active regens with this engine since Cummins utilizes a 3-way catalyst for emission control,” Haygood explained. “What’s more, body builders will not have a problem with the engine or placement with the fuel tank (45- to 80-gallon options), which will streamline upfits.”
Reaching New Class 5-6 Markets
Haygood said new markets may also emerge for Kenworth thanks to the new engine since some fleets that run Class 5-6 medium-duty trucks run an all-gasoline fleet and their maintenance facilities are set up for that.
“By spec’ing the Cummins B6.7 Octane engine, new customers can step into a Kenworth and enjoy all the driver comfort and longevity a Kenworth offers while keeping their operations simplified with a gasoline powerplant,” he added.
