people wonder what the largest displacement factory car engine was, here's the biggest piston engine, and the 2nd n 3rd biggest that I've come across

1910 Fiat S76, the "Beast of Turin", 28.4 liter engine that is about 1730 cubic inches, 4 times as big as my 426 cu in Max Wedge. Try and imagine 4 hemis, 3/4's a hemi, or 6 of the hemi cylinders per cylinder in this aircraft engined straight 6 cylinder. Yeah, that is huge, but made relatively little power or torque because engines weren't as understood and developed in the 1910's.

An outrageous creation that debuted in the early 1910s, the Tipo (Type) S76 was built by the Fiat factory in Turin presumably to break the world's Land Speed Record, which then stood at 125.95 mph. The chassis was a flimsy 1907/08 Fiat production unit with a Tipo S76DA six-cylinder airship engine of 28.4 liters (1,730 cu. in.), which developed 300 hp at 1,900 rpm.

Standing about five feet high at the radiator cap, the frighteningly top-heavy car was referred to as The Beast of Turin. Except for a brief appearance in England at the Brooklands racecourse, where it was timed at about 90 mph, it never made an impact on any records and was returned to the continent to be lost during the confusion of World War I. http://www.airportjournals.com/Display.cfm?varID=0611015

The Beast of Turin’s engine cylinder's were so large, a man could stick his head in one. When it drove down the road, flames shot 10 feet out of the exhaust.

Count Louis Zborowski, a racer and racing patron, was incredibly wealthy and his stable included a 1914 GP Mercedes and a 1919 Ballot, and he raced a Bugatti at Indianapolis. He returned home with a new American Miller race car.

Chitty I was created in 1921 after Zborowski obtained a war reparations Maybach aero engine from a Gotha bomber. The 23-liter (1,409 cu. in.) six had four overhead valves per cylinder. At a modest speed of 1,500 rpm, it put out 300 hp. The chassis was an old Mercedes that had been lengthened and topped by a primitive aerodynamic body. To show it was all in fun, the exhaust pipe ran the length of the body and culminated with a turned-up tip with conical shield.

1912 Mercedes with a 21.5 liter engine, only 4 cylinders and was already posted at
http://justacarguy.blogspot.com/2009/10/if-you-have-wondered-what-largest.html