ok for the 5.7 vortecs, when you get headers there are ones that have A.I.R. tubes and then others dont. first what are they? second they would be on the back of the right manifold right? i dont think my truck has them. but im not sure.

thanks

 

the AIR system in GM vehicles sends air from inside the engine compartment to right before the cats at startup, which gets them going quicker. It's purely an emissions system, and should be ripped out.

It just gets the cats working faster than they would by themselves. If you remove the system, you'll get an SES light after a while, but a tune can get rid of that.