Please Help I.D. This Air Breather

it is a 1970 383 440 base from a cop car. the stickers are a give away it is for a cop car to me. warning about the proper thermostat to use to prevent over heating. i do belive the top is generic it is mismatched and does not go with it. here is a link to a picture of a regular car w/ emissions http://www.nicksgarage.com/aircleaner/70_383ds_08.jpg

what do you think?