The BBK RD department developed these headers with one thing in mind Getting even more horsepower and torque out of the all new 2015 - 2017 Coyote powered 5.0 liter S550 Mustang GT. This all new BBK header design is constructed with 1 - 34 CNC Mandrel - Bent tubing and solid 38 laser cut exhaust flanges to prevent heat distortion. Initial testing has showing gains of around 14 horsepower with this bolt on. These BBK tuned length exhaust headers include detailed instructions on how to cut and weld the factory drivers side OEM converter from the factory headers to the new BBK drivers side header flange for installation.