ok i have a 5.7L 350 tpi and it has just stock exhast manifolds on it, now im switching to headers probably headman. but my question is why are normal headers only like 200 and smog leagal ones are like 500-800? i know the only difference is that air is pumped in to the headers to help burn off any residual gas in the exhaust. but what would stop you from dilling and tapping fittings into non-smog legal headers and putting air into them basically making them smog legal? one question i have is my camaro has a air pump on the stock manifolds, if i just take that off and put on normal headers is that going to affect my on-board computer? does it afftect things like gas milage or bring up error codes? im just wondering what is involved in making aftermarket headers work with the computer that are not smog legal.

 

The stickies at the top of this forum pretty much answer all your questions.