Process West Street Air Box Kit for Ford Falcon XR6 Turbo FG [PWFGCAI01]K&N Filter Supplied 6" to 4" bell mouth Suites factory turbo The new Process West Street Air Box is now available. Designed to replace the factory restrictive air box and part of the factory intake tract. The Street air box has the same DNA of the 4" race air box system. Utilising a massive 6" ID K&N filter mounted to a custom spun aluminium trumpet into 4in mandrel bent aluminium piping for maximum flow. If you want a loud high flowing intake this is