Hello I own a 1984 Chevrolet Camaro z/28 it has a 305 motor with smog system. I cannot figure out what part this is does anyone have a clue what this part is?

 

I'm not sure of a correct name, but it looks like the same part I have in line from my power brake booster and the vacuum port in the rear of my carburetor. Seems to be some type of check valve.

 

Looks like a air inlet muffler/filter for the smog pump.

 

It's a Silencer Assembly. See attachment.

 

Agree with TTOP350 and Paulo... muffler/silencer.

Air is drawn into the smog pump through the front slots, behind the pulley. When air is not going into the exhaust manifolds nor to the cat, it has to go somewhere... which is back to the atmosphere. If you just dump it, you'll hear the pulsations of the pump pressurizing the air, somewhat like a blow-off-valve. GM didn't want this mystery noise to appear at certain times, therefore an air pump outlet muffler.