The ONO started its life as a S74 Fiat; one of three factory cars brought over from Italy to race in the 1911 Vanderbilt Cup in Savannah, CA. It became the "ONO" in 1914 when the original Fiat engine broke and was replaced with a Pope Toledo motor and radiator.
As a Fiat /Pope it had quite an illustrious racing career. In 1912, Teddy Tetzlaff set a world speed record in the Fiat at Santa Monica, CA. While it raced with Bothwell's vintage racers in the early 1950s, it was not part of his collection
Notice that the grill is protected from rocks and trash by a stiff screen that is nosed out to help in aerodynamics and possibly to increase the area of the screen so as to not decrease the airflow
Dual chain drives, is that the same as posi-traction? I think it must be
See Tere's gallery of the Ono at http://justacargal-s.blogspot.com/2011/06/race-to-fair-2011-pt-3.html
for more about Bothwell's car collection, from Sports Illustrated in 1957: http://sportsillustrated.cnn.com/vault/article/magazine/MAG1133626/index.htm
or read the article and see the photos from a 1951 motor car magazine of Bothwell and friends racing on Catalina Island that I posted http://justacarguy.blogspot.com/2009/08/racing-on-catalina-in-summer-of-51.html