I have an Oliver 550 I think. The S/N tag reads as follows:

550

Model # 65-71181

Serial # 186 341-482

Does anyone know what this tractor actually is? I am not so sure it is a 550, but i could be wrong and i have no clue what the year is. Also if you could explain to me how you got the model and year off the tag i would greatly appreciate it.