Rich, I used this motor as a outlaw motor in 40 stock tunnel, it had a os muffler on it and it ran pretty good. But the stock carb (which is missing) always seemed like it was sucking air and it would quit when you back off. I don't run that class anymore and still have my older version Nelson. I had to get a new p/s for my old motor and got them thru Otto who got them from Henry Nelson. I was told he has plenty of parts.