NICK, keep filing. If you drill the hole too big on the intake tube, that air sensor's gonna fall right in, and you will have a worthless piece o'**** intake tube with a big frickin' hole in it. File the square edge just enough to fit it tight at intake tube with the outer round base (on the connector end) of the sensor. Finish it up with a silicone bead, or gasket goo. I Hope you didn't drill out the hole with the intake tube on the car...