This block is several years old but just now I cut two shutters into it on the driver's side. I used to take it out for above freezing temps because my fanless truck told me to. Perhaps it can stay year-around now.
The shutters in the coro have living hinges but the great part is the latching system- simply a bevel cut such that I force the shutter past the bevel to lock it shut, all from a grille opening. I only closed one shutter in the second pic for show but they both operate the same. Singly or in tandem, as conditions dictate.
The mis-matches between grille openings and block were necessary to clear the various supports and whatnot behind the grille yet in front of the radiator. Some flat black paint will help the aesthetics.
The hole on the passenger side has no shutter as it's for the trans cooler and is always open.