Are there any direct fit headers for a 1968 GTO?
 

I want to put a reasonably priced set of aftermarket headers on but I'm concerned with clearances and or parts being in the way.Are there any brands of aftermarket headers that will bolt on a stock 68 GTO without having to make mods to the headers or the car?, it has air,p/b and ps.If not then what mods would be needed for them to fit?
Thank You