Tips and Pics of custom headers
I believe Tubular Automotive still produces make your own kits in any size you want. The kit consists of flanges, all the bends you would need and collectors in several different sizes for your outlet. They also offer an adapter plate set up that consists of a flange plate that bolts to your stock bolt pattern and an outer plate that spreads them so that you can use round tubes into the flange. You may want to seperate the flanges into 3 pieces so that they are easier to install. They also produce a header that fits this application. I believe the part number is a TDR-8. They are in Rockland Ma. 617-878-9875