Welcome to strokers. It's also a 97 engine in an 01, anything 2000+ is cali emissions, so it would have 2 pre cats, with an o2 before and after each. One cat per "bank" 1-3 and 4-6. Running the 97 header as that was what was on the engine so now I need to pull it and weld o2 bungs on for propper...