I've heard the airbox is actually from the Mustang. The inlet goes through the left inner guard instead of up to the bonnet like the old snorkel. So you'd have to be prepared for some inner guard cutout work. Don't know what the gain would be for a standard 302 motor though - they only suck so much air in, and surely Tickford got the intake right at the time?
AUIII XR8, Manual. Herrod Motorsport bits