Depending on the year they either have 20 HP or 23 HP. They also dont have the reverse PTO lockout switch on the dashboard like the 3100 series.
Instead its a simple metal tab underneath the foot pedals that get removed.
other than that they are really good machines, and hold up well ( I have one, so do others on the board)
I'm also a happy owner of model in question with no regrets. I bypassed the reverse lockout within a couple days of purchasing the tractor and wouldn't think of reconnecting but then I don't have any younguns to be concerned about.