Gents, Yes the Dzus is more original to the car, however I decide to go a different route.
I did not create a workable vent for the center NACA, but also did not want to just leave it un opened and painted.
What I did was to fab a billet aluminum filler piece that fills the NACA hole (attaches with two countersunk machine screws from the back side), then the bottom of the filler has a male "V" pointing downwards that slides into a billet female "V" which is attached to the chassis. That centers the front clip left-right, up-down. Then, in the lower portion of the male "V" theres a 3/16" hole in it to accept a T-pin. The front clip isn't going anywhere with that pin in place.
I don't have any pics to share at the moment, but will post them soonest.
Thanks,
Doug