Hey, What does this part do ? does it cost alot ?

thanks

 

Well I don't know about the LT1 but on the LO3 it pumps hot air into the cat to help burn hydrocarbons on a cold engine. I think.
Some please correct me if I am wrong.

Mine is off right now. I have to put it back on to pass inspection next week.

I don't really have too much use for it. There are not too many days here in Phoenix where my engine and cat don't get hot enough. But it has to be on to pass visual inspections.