Now, any genuine Miller engine is special, and the most coveted model is the 91-cubic-inch supercharged jewel that set speed records that still seem incredible to this day. But Castle believes that his engine is what you might call the Rosetta Stone of Miller engineering. It's the oldest surviving, and quite likely the first, of the 183-cubic-inch straight eights that launched the Miller empire. A slightly modified version won the 500 in 1922 and formed the foundation of the Millers that dominated Indy-car racing for the rest of the prewar era. Castle's engine also established the fundamental architecture of the Offenhausers that won every 500 from 1947 to 1964 and continued to race at the Speedway until 1980. So it's not too much of a stretch to call his engine the most influential racing motor in American history.
This project was particularly appealing to Castle because he's an engine man with lifelong ties to the Indianapolis Motor Speedway. He lives so close to the track that he can hear engines wailing around turn 4 when race cars are circulating. As a young man, he moonlighted as a race mechanic during four consecutive Indy 500s, wrenching on Offys derived from the Miller he owns today. And he spent his professional life as a chief project engineer for several projects at the nearby Allison plant, most notably the Allison Model 250 gas turbine, one of the most successful helicopter engines in aviation history.
Over the years, Castle has restored -- in some cases "resurrected" would be a more apt description -- a remarkable array of derelict machinery: A 1910 Hupmobile. A 1904 Oldsmobile. A 1914 Metz with friction drive. A seven-passenger 1912 Winton. A 535-cubic-inch 1908-9 Stearns with double chain drive. A 1929 Cadillac Sport Phaeton. A 1910 two-cylinder Buick. Parked on either side of the Miller in his garage are a 1911 Cadillac and a 1926 Bentley that he and his wife, Esther, have driven from Maine to Florida, Texas to Michigan. So for decades, the Miller engine sat in the basement, forlorn but not quite forgotten.