 Pliny E. Holt, the son of Benjamin's half-brother, William Harrison Holt, had been working with Stockton Wheel Company for the past nine years. In 1906, he was named president of the newly formed Aurora Engine Company, named after Aurora Street in Stockton where it was located. The new company manufactured gasoline engines to replace the large, heavy steam boilers used to power the earlier Holt tractors. A gasoline engine considerably reduced the overall size and weight of a tractor, produced more power per pound of weight, and reduced the tractor's cost, making it more cost-effective and affordable. Holt's most popular gasoline engine tractor was a Model 75, weighing 24,000 pounds (11,000 kg) with a 75 horsepower (56 kW) engine. Pliny was also treasurer of another subsidiary, the Houser and Haines Manufacturing Company of Stockton, from 1905 – 09.
