About 2015 Ford F-350 Super Duty The 2015 Super Duty achieves best-in-class towing performance with a second-generation 6.7-liter Power Stroke V8 turbo diesel engine that has been further developed to provide more power, torque and efficiency. Ford's second-generation 6.7-liter Power Stroke V8 turbo diesel now boasts 440 horsepower, up from 400 horsepower, and 860 lb.-ft. of torque, up from 800 lb.-ft., across all Super Duty models from F-250 to F-450. The 2015 F-450 tops the F-Series Super Duty pickup truck lineup with maximum fifth-wheel/gooseneck towing capacity increasing to a class-leading 31,200 pounds, a gain of 6,500 pounds. The truck's gross combined weight rating increases to a class-leading 40,000 pounds, a gain of 7,000 pounds. The F-350 increases maximum fifth-wheel/gooseneck towing capacity as well, to 26,700 pounds, from 23,200 pounds, and the gross combined weight rating goes up 4,500 pounds, to 35,000 pounds. The improved ratings are a result of designing and engineering the truck as an integrated system. This approach has enabled Ford engineers to optimize performance across the full Super Duty lineup. F-350 Super Duty is available with a high-capacity towing package that includes new front springs and a wide track axle, increasing the gross combined weight rating with the 6.7-liter Power Stroke engine from 31,900 pounds to 35,000 pounds. Improvements to F-450 that allow it to handle the increased tow rating include commercial-grade 19.5-inch wheels and tires, upgraded rear U-joints and suspension components with new leaf springs, front and rear stabilizer bars and shocks. The steering system has stronger gears and linkages and the fifth-wheel/gooseneck has increased towing capacity.