According to CARB's website: Database: Aftermarket Parts Database of Executive Orders
JBA is only CARB approved header for
2004 3.8L Mustang
Also, make sure your engine is a 3.8L V6 and NOT a
3.9L V6. No one makes a CARB legal 3.9L V6 header.
It doesn't matter if the Stock/OEM Exhaust manifolds
are the same.