I would take another look at the CFM... For racing applications, you want a higher flowing carb (my rule of thumb is cubic inches x 2 for 7000).

The formula I've seen is CI * RPM / 3456 * VE where VE is volumetric efficiency... we use about 85% for street cars and 110% for race cars.

I would use a 850cfm carb at the very least on your motor and a 950cfm would be better.

With 230cc heads, the carb is your bottle neck....

BTW: welcome aboard

Two cents,

-Chris