SteveJa, I have one with about 2.5 gallons on it and it still has plenty of compression and runs really well. I just ran it yesterday and it did everything I wanted it too, it has a lot of power down low and spools up very fast plus it gets very good mileage. I came in after a 5min qualifer with a little more then half a tank with the stock 8mm venturi. I have found that the powerband is not as smooth as the 5 & 7 ports but that could be helped with more time playing with pipe and clutch combos.