Are the factory manifolds cast? Mine look to thin to be cast. Does this appear to be an OEM unit? I assumed it was...
The factory headers are stainless, but the stainless is a 400 series. It's not what you would use to make pretty knives and forks, or shiny trim for the grill. To some people, "non shiny" is low grade. :wink: The advantage of the 400 series for exhaust headers is that the coefficient of thermal expansion is lower than for the "high grade" shiny stainless, or the high nickel 300 series alloys.low grade stainless