if you look at the tb, on the back side(faces the fire wall) there is a indentation that goes half way around the tb. you need to fill that with epoxy and let dry(over night to 24 hrs to be sure it dried). then take a dremmel and bore out the inside of the tb so that it is a circle and not an oval and also grind off all the little fins that are in it. do not bore it out any wider than the throttle plate. during the grinding you will go through the plastic and into the epoxy so dont worry. make sure that the tb is sanded smoothe inside, then clean it out very good so you dont suck anything into the motor.