A fellow locally advertised this for on craigslist. he said he thought it was a 600 series but didn't know for sure. it has live hydraulics, still 6volt, 4 speed tranny, so I guess I had a memeory lapse cause I bought it. the fellow drove it over to my place 5 miles away. never saw any smoke on the way. stil sounds good, don't see one drop of oil so I think its a pretty good tractor, amp and proof meter are bad so I will have to replace them. not sure if the generator works or not. please look at the photos and give me your opinon asto what you think it is. serial no is 753-- whitch I think is a 1955 and I think maybe a 600 series but the front emblem doesn't say that. all help needed. thanks norm