I agree with what Jeff Lee is saying. I have fixed this problem a few times before. You can sink the valve/seat, which in most cases can reduce 3cc's or more depending on the valve diameter. And in most cases will increase the flow and air speed thru the port. Call or email me if you need help with this.
Best Regards,
Chris Hardy
231-773-7252
chrishardy@racingenginetechnologies.com