I volunteer at the Age of Steam RR museum here in Dallas, and we have some big honking 6's out there. Our M160 powered baggage car has a 6-576 diesel (576 ci per cylinder), and we also have a Fairbanks and Morris 1200 Hp diesel which has 6 cylinders, but 12 pistons which meet in the middle to make compression (dual cranks). The overall winner though is the DD40 which has twin 16-645 diesels (645 ci per cylinder) for 10,320 cci and a tractive effort of 136,000 lbs. The steam equivalent there would be the union pacific 4-8-8-4 "big boy" locomotive which weighed 1.2 millon pounds (with tender fully loaded) and a mere 7000 hp. You never turn a bolt there without at least a 6 ft. cheater on it!
(and the excutive director drives a 60 chevy pickup with a 6 to boot!)
