The factory 7.3L Powerstroke Up-Pipes are prone to failure at the factory bellows-style flex joints causing power robbing pre-turbo exhaust leaks over time. But, deleting them altogether in favor of straight tubing can cause serious long term damage from heat expansion and vibration that can cause stress fractures and more exhaust leaks. With the Sinister Diesel Up-Pipes for the 7.3L Ford Powerstroke, we have instead opted to use much stronger and longer lasting “double slip” joint. The new design still allows the upper and lower sections of the Up-Pipes to move due to heat expansion while maintaining a complete seal. The double slip joints even allow for some flexibility to accompdate aftermarket turbo kits. Sinister Diesel 7.3L Powerstroke Up-Pipes are made from stainless steel tubing, solid stainless steel CNC flanges, and include the factory cast merge piece. All seams are TIG welded on a fixture for precise fitment tolerances and then back-purged for the highest quality and strongest welds possible. This Up-Pipe kit is designed to fit the 1999.5-2003 7.3L Powerstroke Super Duty and is available in Raw Stainless, Ceramic Coated, or Wrapped finishes for extra protection, durability, and a clean and stylish appearance.