The company’s new turbocharged B6.7 will reportedly see use under the hood of medium-duty Kenworth trucks

- Diesel engine firm Cummins just revealed its first gasoline-powered engine
- The new “B6.7” is rumoured to be destined for medium-duty Kenworth trucks
- Its turbo’d, runs fine on pump gas, and offers 300 hp and 660 lb-ft in top trim
A name all but synonymous with stump-pulling diesel engines has just launched its first ever gasoline-powered mill. Fetchingly called the “B6.7” (no one said engine-makers were good at coming up marketing) Cummins says it has been specifically designed and developed for the medium-duty market. That means machines like school buses, big delivery vans, and vocational trucks.
Cummins hopes for a 10% bump in fuel economy over other gasoline-powered engines, depending on duty cycle. This would be welcome in the medium-duty world, where your author once experienced first-hand the terrifying thirst of a fully laden 26-foot U-Haul moving truck powered by a gasoline engine.
Estimated torque curves show the gasser hitting its stride around 1,600 rpm, depending on the state of tune, compared with a typical Cummins diesel, which is hauling the mail at about 1,200 revs. The gasoline-powered engine continues pulling to its 3,200-rpm redline, at which point the diesel is long since dead and buried. The brand alleges over two million miles of testing.
Who’s the customer for such a mill? It is being reported that Kenworth is launching a line of its medium-duty Class 5 to 7 commercial trucks with this engine. It also could be a boon to fleet owners dealing with machines working in places where access to diesel fuel is not plentiful; this B6.7 runs just fine on plain old regular 87-octane.
Sign up for our newsletter Blind-Spot Monitor and follow our social channels on X, Tiktok and LinkedIn to stay up to date on the latest automotive news, reviews, car culture, and vehicle shopping advice.