Most people are aware that on 6cyl EL/AU falcons the airbox lid has an outlet of 55mm which is a restriction. Most probably ford used to keep induction noises down.




By removing the inner rubber pipe you can increase the diameter of the exit to approx 66mm-70mm. This will result with better throttle response and mid-top end power.

Step1- Remove the 4 bolt adaptor (8mm bolts)

Step2- Screw 4bolt adaptor onto wooden block or hold in vice.

Step3- now use a holesaw approx 66-70mm and drill out the inner pipe. Making sure you don't scuff the outer rubber lip and leaving the internal bellmouth undamaged.



Step4- Bolt airbox adaptor back on lid and enjoy.

Pics below use a golf ball as a comparison of size.








Cheers....