These headers are designed to fit the 3800 Series II that has been retrofit into the Fiero. This places the exhaust outlet in the same area as the stock Fiero exhaust. These headers are standard 1-1/2" primary 16 gauge head pipes with 3/8" thick flanges or marmon clamps. The "Y" pipe is made of 2", 16 gauge tubing and is connected to the 2-1/2" "Y" pipe collector with a 2-1/2" 3 bolt flange. The exhaust system on the Stock 3800 exits on the wrong side of the motor. These headers solve the problem of Catalytic and Muffler installation.These headers are now available for purchase with marmon clamps (pictured below) in place of the 3-Bolt flange for an additional charge. Please specify when ordering. This Header System comes shipped as raw metal. They may be painted with high-temperature paint by installer.