What you are after is called a Radiator Deflector Panel but it is
NLA from Ford. It stops the air coming thru the front from taking the easy route under the radiator.
As suggested the wreckers is where you may find one but finding an undamaged one may take a while. There are also two "hanger brackets" one each side that attach to the chassis rail and a screw goes up thru the panel into the bottom of the hangers for more support.
The panel is the same for an AU base model , XR, Fairlane or T series