How to Install Stainless Works Long Tube Off-Road Headers w/ XL Leads - 1-7/8 in. on your Mustang

Thanks for purchasing Stainless Works Muscleflow Headers for your 2015 Mustang GT 5.0. We have gone to great pains to make sure that our exhaust systems fit and sound great. Please follow these steps to ensure that your installation goes as planned.

1. Stainless Works recommends the use of Permatex Hi-Temp RTV silicon gasket maker as an option to or in conjunction with the use of factory gaskets. The recommended RTV is Sensor-Safe P/N 101BR or 27BR, available at NAPA and other retailers.

2. Disconnect the battery before starting work on the exhaust system for your vehicle. Reconnect the battery when the job is completed.

3. Your exhaust system can be installed by a weekend warrior but the use of a lift is recommended for ease of installation. If using a jack, the vehicle must be placed on a level hard surface and jack stands are required for safety reasons.

4. Raise and support vehicle.

DISASSEMBLY

5. Remove battery box cover - 3 push clips.

6. Disconnect battery.

7. Remove 6mm battery hold down bolt and remove battery.

8. Remove (3) 6mm bolts holding battery box in and remove battery box.

9. Starting from right side of car remove 6 push clips holding windshield wiper cowl
down.

10. Remove inner battery box panel (8) 6 mm bolts and (2) 8mm bolts.

11. Loosen air box clamp and disconnect wire.

12. Remove air box cover and filter.

13. Remove air box (1) 6mm bolt.

14. Remove lower engine service cover (2) 6 mm bolts and 4 screws.

15. Mark and remove steering shaft from rack by removing 8mm Torx bolt from top side of swivel joint.

16. Remove wires from starter (1) 8 mm nut, (1) 6mm nut then remove starter (3) 8mm bolts.

17. Remove O2 sensors from pipes or disconnect the pipes and remove O2 sensors after pipes are out.

18. Raise up the motor slightly with a jack.

19. Remove right motor mount (3) 10mm nuts (4) 10mm bolts.

20. Remove (16) 10mm nuts – (8) per side- from manifolds and remove manifolds and converters (can come down all together).

21. Remove (16) 10mm studs from heads.

22. With the manifolds out, remove left front O2 sensor wiring from its loom clips (so it will reach the longer position required for install) and remove the left rear one from the front loom clip on the side of the transmission.

ASSEMBLY

23. Seal and install headers from the bottom using either the 10mm bolts supplied or
the factory studs and nuts.

24. Reinstall motor mount and lower the motor and tighten.

25. Put starter back in and tighten.

26. Reconnect steering shaft.

27. Reinstall engine service cover.

28. Install either cats or off road pipes using (2) 3” clamps.

29. Install lead pipes (2) 3” clamps.

30. Reinstall O2 sensors.

31. Based on the product you have chosen, the lead pipes either hook to the factory or Stainless Works Catback.

32. Adjust everything for fitment and tighten all clamps.

33. Be sure to have adequate clearance around all wires, hoses and lines. If anything is in contact with the exhaust system, it will melt. Make sure to have at least ½” of clearance and wrap any suspect areas with DEI thermal barrier wrap.

34. Lower vehicle.

35. Reinstall air box.

36. Reinstall battery box components removed and reinstall battery.

37. After double checking for clearance and making sure all lines, wires and hoses are secured, drive the car for 10-20 miles and re-check all clamps and clearances. Your system may be tack welded at the joints/ clamps to reduce shifting of the system during heating and cooling cycles. Make certain to disconnect the battery before performing any welding.