[HEEP]

Not real sure where this goes, but I was out in the garage pulling apart my Chevelle, again, and the fresh air venting system was still intact, so I removed all of it.
My question, do I need it with today's A/C systems? How do the new systems pull in fresh air? Do I need to clean this thing up to reinstall? It has a door on the passenger side, a door in the top of the cowl, and a vacuum pod mounted in the cowl with a hose running to the interior.

Thanks, in advance for your help,
HEEP