My "new" firebird that I am buying later this week has swapped engines. The 1982 Firebird has a Chevy 383 and I need to pass emissions testing but the exhaust system it has now makes it unable to pass the test. I was wondering if anyone knew if I should purchase a exhaust system that fits a 1982 Firebird, a system that fits a Chevy 383 or if I would have to custom build my own.

Thanks

 

The 383 is not different from a 305 in terms of external dimensions. What is making your current system not pass? Remove that part and install a factory 1982 replacement part then take it back off after inspection

 

what state are you in? some states look for the original smog system and require you to have all factory emissions components in order to pass.