30mm intake for 150cc... should I port the head or...?

[jpark1]

I acquired a 30mm CVT carb and shiny aluminum 30mm 'gy6' intake. It's a VERY tight fit with the engine mount being all in the way, but I got it to work... however, I noticed the 'output' hole on the intake is quite a bit larger than the 'intake' hole of the engine, and the rubber spacers I had to use. Runs ok, tremendous midrange pull and great throttle response, bit of a stumble though, some hesitation...Did I get the wrong intake(possibly for 250cc?), or should I tear off the head and take a dremel to it? I would think it's best to get a smooth flow of fuel/air... right? You guys who went up to 30mm carbs... what did you do?