It looks to be the air cleaner that I need.

Is it for sale?

Unless someone sees some detail that I have missed, it appears to be a 1967/early 1968 A body 383 air cleaner.

http://www.nicksgarage.com/aircleaner.htm
According to Nick, about a third of the way down the page, it was also used on early (early not defined) B bodies.

If it's for sale, let me know. I'm sure the people here will help settle on a fair price. I know it's in the hundreds.

Bob

AAR 4-speed 3.91, Tor-Red;
70 440 6 pack Roadrunner 4-speed 3.54, Plum Crazy;
68 Formula S conv 383 4-speed 3.23, Electric Blue;
69 Barracuda conv Slant 6 OD4 2.94, 71 B5 Blue;
78 Lil' Red Truck, Red;
70 Challenger S/E. 505 6 pack, Passon 5-speed, 3.55, B7 Blue