2001-2004 Duramax LB7 High Pressure Injection Line (4 and 5) (FPE-FL-LB7-45)Original LB7 Injection lines will corrode and break and are a leading cause of contamination when changing the injectors. If you are changing your injectors, have a line failure, or are looking to upgrade your stock lines, we've got you covered with our direct replacement LB7 injection lines! An upgrade to the factory lines on your 2001 2004 Duramax LB7, our Fleece Performance lines feature machined 4140 injector swivel nuts and are corrosion