JBA Stainless headers Rusting

[Tahoez71]

409 is what most factory exhaust is made off. In the northeast 409 will last a good while. 409 is used on exhaust vs 304 because it doesn't expand as much when heated. I was told this by a performance shop. A full 304 stainless exhaust can grow almost 2 inches fully heated from driving. 409 will last a good while. My truck is a 99. The factory y pipe is 409 it's still on my truck.