The W400 series of tractors were built in 1955 and 1956. There were 1118 diesel W400 tractors built. The 4 cylinder diesel engine had 264 cubic inches and produced 47 hp on the drawbar. The W400 replaced the SWD6 and was replaced by the 450. The W400 was also built with propane and gasoline engines. Our W400 is serial # 3337. It was built in 1956. It came from a former customer's farm at Snowflake. We have the W400 gas tractor in our collection too.