Spy Shots—Smokestacked Ford F-350 Source: SEMA The shooters at KGP Photography caught a Ford F-Series Super Duty prototype sporting some serious, big-barreled smoke stacks. The 'stacks are clearly functional, as the cool, moist air has resulted in lots of smoke billowing out. It's unclear what to make of this one, as its not your traditional factory exhaust treatment. The shooters have seen this prototype making several test runs throughout the Dearborn, Michigan, area, and it has been frequenting Ford's usual test and development labs that are actively developing the Blue Oval's next-generation models. They have seen this 'stacked F-350 leave one lab just minutes after a mule for the next-generation F-150, so the fact that this prototype is registered on manufacturer "M" license plates, like every other prototype and test car running the streets of Dearborn, shows that it is part of some Ford testing program, whatever that may be. Is Ford developing a smoke stack exhaust for production trucks? Who knows, but its an interesting curiosity to see as part of the Detroit test scene.