This coarse screen inside the cowl (below the wiper drives) should keep most of the leaves out of the R side, where the fresh air intake is. Cutting the edges to fit the internal contours of the cowl while remaining straight at my chosen tilt angle took a few tries...

I've since learned that Ford published a TSB about this in the early 80s.

This one is also relevant.

Owner caption October 2012 · Photo 4772 of 5000