What "billet" head do you have?
Squish band is set by milling the top of the cylinder, not by turning down a hopefully well designed head.
How are you going to get your motor to 11,000 rpm?
Why are you aiming for 11,000 rpm?
How is your NT carb SEALED onto the intake tube?
I use an O ring to seal, but you could use some kind of goop.
You are sucking air in through that unsealed connection that is making your motor rev high.
When you have the carb off to seal, make sure the slide is snapping back down when you...