I changed up the design of the firewall some. The change affected the shape of the intercooler flange wells. I decided to stamp the parts, I guess mainly because I wanted to give stamping a try.
I cut dies out of 3/4" MDF board & stamped the sheet metal on the press.
then I rough trimmed the parts.
cleaned them up
Welded the front & back halves together
Once I had the tube flanges where I wanted them I welded them together.