This NACA duct is 3D printable and will fit in the headlight lid of an NA Miata with no modifications to the headlight assembly. Cutting and modifications of the lid itself will be necessary.

To mount, make the centerline of the duct 3 3/4" and parallel with the inside edge of the headlight lid. Then move the duct as far toward the back of the car as possible. This alignment ensures clearance of the headlight assembly.

Send me a message if you have any questions about mounting or finishing or see ​http://www.tommyhaake.com/current/#/naca/ for more info.

If you don’t have a 3D printer at home, I also sell this product on Shapeways who will print it and send it to you directly. Go HERE to check it out.