"I figured that, sooner or later, Dad would get it assembled and running," says Castle's son, Terry. Like his father, Terry is a retired Allison engineer and old-car restorer who owns a 1925 Bentley and a couple of MG TCs. "This seemed like a good, fun challenge. I've seen Dad take on all kinds of projects, and I've never been able to keep up with him. So this one doesn't surprise me too much."
Restoration projects begin with research. Fortunately, Castle was already a member in good standing of the minute but passionate cadre of historians who obsess over every detail associated with the life and work of Harry A. Miller, the lodestar of American prewar race-car engineering. By this time, Castle had realized that his engine was one-of-a-kind because it had a detachable head, whereas all subsequent Millers, and the Offys that followed, featured a monobloc design. Only two 183s were built in 1920 and '21 before Miller upgraded to a one-piece unit, and the other one had been cut in half in a racing accident. So now it was a matter of figuring out what chassis his 183 had been in.
Miller had come to prominence in 1917 as the builder of the Golden Submarine made famous by Barney Oldfield. Two years later, millionaire Cliff Durant -- a major-league sponsor and sometime racer who was the son of General Motors founder Billy Durant -- hired Miller to build a brand-new car. Dubbed the Baby Chevrolet in Durant's honor, the car was a gorgeous piece of work. (Newspaper accounts mistakenly referred to pieces made of manganese bronze as being gold-plated.) But the Miller-designed four-banger was a dud and the car was a slug, so the disgusted Durant either sold or gave it to his driver, Tommy Milton. Milton retrofitted the car with a Duesenberg engine. But even as he raced the Duesey, Milton commissioned a new straight-eight 183 from Miller.