Some food for thought at the end of the day the 7 mm venturi insert is going to be the limiting factor on all of these engines... The power loss going from a 9 mm down to a 7 mm is huge, in the realm of 25% power loss or better.... Doesn't matter which engine they all seem to be limited at a relatively similar HP by the 7 mm venture insert..... I Just got done dyno testing the new Picco GT engine and on a 9 mm its an absolute beast, but on a 7 mm its power and RPM is greatly reduced... from 2.5 HP dropping down to 1.8 HP all from the insert change... I Also tested a few Novarossi 7 and 5 ports and they all behaved the same way, every engines power was reduced substantially by the 7 mm insert.. So IMO as long as a 7 mm rule is enforced all the engines are going to be severely choked back from their full power potential... 5 port, 7 port and 9 port will all suffer equally and all be limited to a very similar power level....enforcing port count rules is kind of meaningless if they are all running a 7 mm inserts.no engine will have any real power advantage over another....