Double overhead camshaft, straight 8 with "Sidewinder" supercharged, plus low intercooler. Began life as a 91 cu. in. engine, enlarged to 142 cu. in., and is now 168 cu. in. Driven to 2nd place at 1929 Indianapolis by Fred Frame. As far as can be determined, this is the last "all out" racing engine by Duesenberg.