Oliver 90
The Oliver 90 series of row-crop tractors was a series of agricultural tractors produced from 1937 to 1961 by the Oliver Farm Equipment Company. Beginning with the Hart-Parr 28–44, the series was the most powerful Oliver tractor offering, capable of heavy plowing. Initial development proceeded on parallel lines, with the 28–44 offered with low and high-compression engine options that became the Oliver 90 and 99, respectively. The lines merged with the Super 99, then diverged again with the 950, 990 and 995 models. The series was produced until 1961.
Hart-Parr Model A 28–44
The first heavy Hart-Parr tractor was the 28–44, or Hart-Parr Model A. Following rating by the Nebraska Tractor Test Laboratory, it was marketed with its power rating. It could operate a four or five-bottom plow. Built in Charles City, Iowa, the 28–44 was itself a scaled-up Hart-Parr 18-36, with a engine with gross, and a weight of. At a selling price of $about $1,325, almost 9,000 2844s were sold. A high-compression version was also sold.Charles City-manufactured 28-44s were sold in Canada by Cockshutt with Cockshutt Hart-Parr branding, starting in 1930.
Oliver 90
The Oliver 90 was introduced in 1937, updating the 28–44 with a self-starter and the Oliver name. The Waukesha-Oliver engines came with gasoline and kerosene/distillate options. The 90 was offered only as a standard-tread tractor, with wide front wheels. Compared with other Oliver number-series tractors, the 90s were minimally styled. Production of the 90 ran until 1952. A version with a high-compression engine was marketed as the Oliver 99.As with the 28-44, Iowa-made 90s were sold as Cockshutt 90s in Canada.
Oliver 99
The mainstream agriculturally-oriented Oliver 99 was introduced in 1952, replacing the 1932 Oliver Hart-Parr 99 Industrial Special High-Compression and the Oliver 90. The 99's production was moved from the main Oliver plant in Charles City, Iowa to South Bend, Indiana. Options were added for six-cylinder and diesel engines, and the tractors received styled sheet metal. The 99 was the heaviest Oliver offering, exceeding an operating weight of. Selling price in 1956 was about $3,500.The 99 was sold in Canada as the Cockshutt 99.