smallest tractor in the Farmall line was introduced, the Cub. With a 60-cu. in., four-cylinder engine and a 69-inch wheelbase, the Cub was aimed at small farms which had previously relied on horse-drawn equipment. Like the various John Deere L/LA/LI models, one of the "mechanization-resistant" markets it hoped to penetrate was the small one-mule family farms of the rural American Deep South, but the Cub also sold to owners of larger farms needing a second tractor. Production of the Cub commenced at the newly acquired and updated Farmall Works-Louisville plant (formerly the wartime Curtiss-Wright Aircraft factory in Louisville, Kentucky). Selling for $545 in 1947, the Cub proved extremely popular and its design continued largely unchanged mechanically until 1979. For 1955 in IH tractors, the numbered "hundred series" was offered. Although given slightly different styling and few new features, they were still updates to the models introduced in 1939. The only new tractor in the 1955 lineup was the 300 Utility. In 1957 power was increased in some models and the 230 Utility was introduced. Heavy tractors: the 1950s IH would sell 38,000 TD-18 series tractors between 1938 and 1958. The TD-18 would be replaced by an upgraded TD-18A in 1949 and 181/182 variants in 1955. In 1958 the TD-20 crawler was introduced. 60 Series recall In July 1958, IH launched a major campaign to introduce a new line of tractors, the 60 series. At the Hinsdale, Illinois, Testing Farm, IH entertained over 12,000 dealers from over 25 countries. The series included the first-of-its-kind six-cylinder 460 and 560 tractors. Unfortunately just a year later, these models were recalled due to final drive component failures. They had not been updated since 1939 and would fail rapidly under the stress of the more powerful 60-series engines. Some customers lost faith in IH and migrated to John Deere's New Generation of Power tractors introduced in 1960. 1960s Throughout the 1960s, IH introduced new tractors and new sales techniques. As producing tractors was the lifeblood of the company, IH would have to remain competitive in this field. They both succeeded and failed at this goal but farming was about to change. In 1963, IH introduced the 706 and 806 tractors. Until the 88 series, all numbered seies tractors followed a simple numbering system. The first 2-3 digits was the horsepower rating, and the last number was the number of cylinders, so a 1486 was rated