This engine is equipped with what may be the most famous of all Frontenac overhead conversion heads ever to be bolted to a Model T engine.
Louis and Arthur Chevrolet produced this conversion head in late 1923. It has sixteen valves (two each of inlet and exhaust valves per cylinder) and two chain-driven overhead camshafts. The cross flow design has separate intake and exhaust ports for each engine cylinder. Spark plugs are located in the top of the head.
The "DO" Frontenac head made its debut at Indy in 1924, in a Barber-Warnock car built from mostly Model T components and driven by Fred Harder.
Engine displacement was 122-c.i. (two liters), the limit that year. Barber-Warnock also fielded two other T-based Fronty-Fords, both equipped with the "S-R" OHV heads; Bill Hunt drove one of them, and Alfred Moss, father of Sterling Moss, drove the other. These three cars ran with their usual consistency; no drivers needed to be relieved and their speed would have placed them among the first ten in the 1923 race.
Harder in the Fronty "DO" averaged 88 mph for the last 300 miles. However, the purebred racing cars with their astronomical prices, were developed to such a high degree of performance and reliability that the Ford entries were no match for them.
For the 1926 season, Louis Chevrolet built a brand new Fronty-Ford for Indy. It sported front-wheel drive and was known as the Hamlin Special. Its Ford Model T engine, equipped with the "DO" head, was reversed in the chassis.
Its 91 c.i. displacement was achieved with sleeved cylinders and a shorter stroke crankshaft. Supercharged, the engine turned in excess of 6,000 rpm. Jack McCarver qualified the car in the 9th row ahead of Pete DePaolo's Duesenberg, but lost a connecting rod bearing on the 22nd lap.
In 1932, this car was still running and known then as the Ray Day Piston Special.
Over the years, the Fronty "DO" head on the T engine helped set quite a few records at tracks around the country. Dutch Baumann, driving a "DO" racing car made 52 starts during the 1928 season and won 43 first places.
Several drivers in the Mid-west also had long lists of victories with their Frontys. Notable among them were Gus Schrader, of Cedar Rapids, Iowa and Ira Hall of Terre Haute, Indiana.