Ron S.
409 is one of 10 prototypes built at the Louisville plant, during Oct 5th - 14th 1960. I bought it in east Tennessee from the original owners son, after he asked questions about it on this forum. Original owner was an electrical test engineer at the IH test center at Hinsdale, IL. It now is owned by an individual in New York. S/N's 501-525 were test tractors built in November 1960 and sent to the southern regions of the U.S for 50 hours of testing (per tractor), prior to releaseing the tractor for production. It is known where 15 of the 25 were sent for testing. They were to be returned to IH and sold at the completion of the test period. Limited production of the tractor continued with S/N's in the 526 to 589 range to get the manufactoring methods and assembly line set up and ready for production. The tractor was released for production in Jan 1961, beginning with S/N 590.
I also found and bought S/N 510 from a Cub Cadet dealer in central KY, and I bought S/N 556 from and individual in Scottsdale, AZ. S/N 510 now lives in Massachusetts along with 518, 522, and an IH Engineering prototype #411. S/N 515 is in Mississippi, and 505 and 516 are both in Indiana (different owners). It has been learned that the prototype tractors were built without S/N's, and that 4xx series numbers were stamped into the tractors when/as they were released for sale (to IH employee's) by the test center. That is why 411 has a higher S/N, but is older than 409. Casting date codes on 411 date to the early part of 1960, 409's codes are from mid 1960.