The Model 66 Pierce-Arrow occupies the same position among Brass Era automobiles that the Bugatti Type 41 La Royale does among its Classic Era brethren. It was the largest, grandest, and most potent thing produced by a manufacturer during its time. For collectors of contemporary automobiles, it is, quite simply, the Holy Grail.
The 66 was named for the rated horsepower of its engine, a massive inline six-cylinder mill that, at its introduction in 1910, displaced an immense 714 cubic inches. By 1912 the engine had swelled to nearly 825, and while its name remained the 66, its rating had increased to nearly 100 horsepower. Most important, the long stroke created the prodigious torque necessary to propel the massive chassis and typically luxurious, regal coachwork. For some years this model was recorded by Guinness World Records as having the largest engine installed in a production automobile.