Copied directly from Simple Tractors website history
"From 1965 to 1983, the Allis-Chalmers Corporation owned Simplicity Manufacturing.
During the 1950’s, the United States became increasingly suburban, creating the need for riding lawn mowers. The major farm equipment manufacturers wanted to expand into this new market. John Deere and International Harvester designed and built their own machines. The others opted to buy from a firm with an existing product line to re-label as their own. Allis-Chalmers went with Simplicity Manufacturing. In 1961 the first Allis-Chalmers garden tractor, the 7.25 horsepower B-1, was born. Except for paint, decals and minor sheet metal changes, it was identical to the Simplicity 725. In 1963, the B-1 was replaced by the 9 horsepower B-10. In 1965 the B-10 became the Big-10 with a new 10 horsepower engine. In 1966, the Big Ten reverted back to the B-10 when the new B-12 was introduced. Up until 1971 all Allis garden tractors were painted yellow and were powered by Briggs engines.
During 1965, Allis-Chalmers purchased Simplicity. The federal government challenged the purchase. Due to the fair trade laws in effect at that time, the government claimed that Allis-Chalmers controlled too great a share of the market and thus limited competition. As a result, in 1967, Allis-Chalmers opened a new plant in Lexington, South Carolina to build garden tractors. The first models built there were the B-207, B-110, B-112 and HB-112. The B-208, B-210, B-212, and HB-212 were introduced in 1970.
Simplicity tractors continued to be built in Port Washington, but for the first time there were differences besides paint and decals. In 1971, the 300 series introduced many design changes. The body was painted orange and the hoods painted cream, and Kohler engines were used for the first time. In 1973 the similar 400 series was introduced. These tractors bore little resemblance to the Port Washington built Simplicity models. The mower decks and many of the attachments were different. Also in 1971, the B-207 and B-208 were updated to the new paint scheme, but retained Briggs power. The 206, 207, and 208 were continued as the Homesteader series from 1972 to 1974. Also in 1972, Allis-Chalmers introduced the model 616, which was the Simplicity PowrMax with orange paint and a different hood. The 616 became the 620 in 1973 with the new 20 horsepower engine. In 1975 the 620 was relabeled as the 720 to match the numbering of the updated smaller tractors. To the best of our knowledge the 620 and 720 models are identical except that the later 720’s had an upgraded front axle. AC later came out with a second model 616, which was a painted over Simplicity 4216 and had no relation to the earlier “PowrMax” 616.
During the Nixon administration, most of the fair trade laws were repealed, so in 1973 Allis-Chalmers closed the Lexington plant and transferred all production back to Port Washington. Once again, AC and Simplicity Garden tractors became identical except for paint and decals, although certain individual models may or may not have had an exact Simplicity counterpart."
There is a lot more but there are some dates to explain things Source>>>>>> http://www.simpletractors.com/Main/history.htm#Allis-Chalmers <<<<<<<
Re: Allis Chalmers 416 in reply to oldhousehugger, 02-06-2013 20:30:19
I will agree all of them were simplicity's except the 300 and 400 series, they were built in North Carolina, by allis chalmers themselves, then they must of figured it was easier for someone to build them for them, they went back to simplicity win the 600, 700 and 900 series.
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