The 800 series was built 55-57, the 801 series was built 58-62. I have the diesel in my 841 and love it. The power steering is needed if you're going to put on a loader unles you like realy big arm muscles. I have heard different opinions on the SOS those in favor say maintenance is the key and since you have a diesel at least you have that in common. The detractors mention a shortage of expensive replacement parts. In good running condition I think $4800 is in the ballpark. I think that the tractor would be quite usable on your horse farm.