I have the 47HP (but green) I run a 5 ft because I had it from before I really don't know it is there. I want at least a 6' but am contemplating a 7 ft although I am kind of on the edge in my thinking. I don't think you would have any problem with a 6 ft unit there are many TBN members running a 6 ft on tractors in the lower 30 HP range.