I think people have been using aluminum or plastic flanges of the correct diameter for the piping. I think the Z1 stuff is 2.5” so a 2.5” flange is what you’ll need. I picked up two off Amazon (used for vacuums I think) and should be good enough for warm temps. The aluminum ones used in the DIYs (
http://www.the370z.com/diy-section-d...ur-airbox.html) are from an aircraft store. Most people place them at the fang vent opening (there is a little block off plate there). There will be some hole-making involved, so obviously do this at your own risk.