CNC Bored to .625 using a special GX 140 E-Tube, this carb is tuned for use with methanol.(Now allowed in the builder prepared class) Airflow has been significantly increased by opening and reshaping the Venturi using a CNC machine - the same technology we use to bore our connecting rods. Our carb will pass BP tech. The choke shaft and butterfly has been removed and the shaft hole has been plugged for the BP carb. You will need to adjust the black plastic phillips head idle speed adjustment screw to set the idle speed on your engine to approximately 2000 RPM.