The 1929 Duesenberg J-175 Dual Cowl Phaeton was powered by a formidable 6.9-liter (420 cubic inch) straight-eight engine, designed by Fred Duesenberg. This advanced engine featured dual overhead camshafts and four valves per cylinder—cutting-edge technology for its time—and produced an impressive 265 horsepower. The straight-eight’s performance and refinement made the Model J one of the most powerful and prestigious American cars of the era.