These headers and "Y" pipe are designed to fit a 3800 Buick engine that has been retrofit into a Fiero. This places the exhaust outlet in the same area as the stock Fiero exhaust. Standard headers are 16-guage,1-1/2" primary with 3/8" thick flanges.  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 or marmon clamp. Performance headers are 1-5/8" primary 16 gauge head pipes with 3/8" thick flanges. The "Y" pipe is made of 2-1/4", 16 gauge tubing and is connected to the 3" "Y" pipe collector with a 3" 3 bolt flange or marmon clamps.The headers are constructed with mandrel bent tubing and TIG welded throughout available in 1018 steel or 304 stainless steel . WCF headers will give your 3800 Buick engine significant torque increases in the 1500 to 5500 rpm range.This Header System ships as raw metal. They may be painted with high-temperature paint by installer. WCF may also ceramic coat the headers with an additional cost.