You sure that's from a CB550?
The elbow on the side routes up to the engine breather.
There should be a low point drain, and a pocket for the metal water/oil separator in the bottom of the box.
The low point drain hose has the slit/pinch tube end, allows water to drip out and block incoming dirty air.
The plenum box is a drain incase the carbs overflow gas and fill the chamber. Originally it had a molded reduced diameter hose (to about 1/8 inch opening, with some open cell foam stuffed in it to block debris and insect from entry.
Below is what you need. The tray/air box cover is for a K model, the F had a curved horn atop the filter case, as in the second pic.
Cheers,