Wonderboy 575

[MikeH 0]

This past weekend I purchased the above mentioned tractor at an auction. I performed a search of this site and then sifted through the "tons" of information on this tractor. However, I found some information that was inconsistent. One article says the 575 w/o electric start was made in 1959 and in 1961 (both the same model #'s). Does this mean the 575 was produced between 1959 and 1961? If so, is there a breakdown of the serial #'s for each year. Another article puts the date of manufacture at 1958. I was hoping someone can pinpoint the year of manufacture.