International Truck has started production of its first International WorkStar vocational trucks powered by the Cummins ISB6.7 engine, the company announced. Both the WorkStar and the International DuraStar medium-duty truck are available with the ISB6.7 as an engine option."Production of the WorkStar with Cummins ISB6.7 is an important milestone in meeting the needs of vocational customers by providing a comprehensive offering of proven components," said Jeff Sass, Navistar senior vice president, North America truck sales and marketing. "The WorkStar with Cummins ISB6.7 gives customers a winning combination of performance and strength."According to the company, the WorkStar boasts multiple-frame rail options, a double-sided galvanized steel cab protected by an extensive five-step corrosion protection process, and comes standard with the Diamond Logic electrical system. The addition of the Cummins ISB 6.7-liter engine expands the WorkStar model's extensive powertrain options, which include Navistar's proprietary 9.3-liter and 13-liter offerings. WorkStar is also available with a suite of traditional manual and automated-manual transmission offerings from Eaton and fully-automatic offerings from Allison. The Cummins ISB6.7, rated up to 325 horsepower and 750lb.-ft. torque, features flexible horsepower and torque ratings, with higher ratings specifically for fire and emergency applications, the company said."The International WorkStar with Cummins ISB6.7 is the right truck for a large portion of our vocational customers," said David Hillman, vice president and general manager, International Truck Vocational Product Line. "Customers don't have to compromise. They can have it all—efficiency, comfort, capability, and now the proven Cummins ISB6.7 engine."