How to Install Stainless Works 1-5/8 in. Catted Long Tube Headers (05-10 GT w/ SW Cat-Back) on your Ford Mustang

1. Exhaust installation is best performed on a lift by a qualified technician.  Before starting any work, make sure that vehicle is adequately supported before starting, and raised as high as possible to ease removal of the manifolds & installation of the headers.

2. Disconnect battery, and remove air box for easy access to dipstick and tube.  It will be easier to remove the right front O2 sensor if the battery and battery box are removed.

3. Leave the left front O2 sensor in the manifold, and disconnect the wiring harness to it and to the (2) lower O2 sensors.

4. Remove the factory exhaust system starting at the rear of car.  It may be necessary to have the exhaust system at full droop to aid in removal and reinstallation.

5. Remove the bolt holding the steering shaft to rack, and remove the left mounting bolt holding the rack to the frame.  Before moving the rack, mark the location of the rack on both the rack and frame, so that the rack can be re-installed in the exact position it was removed.

6. Loosen right bolt holding rack to frame but do not remove.

7. Pull left side of rack forward and pop steering shaft off.  Push steering shaft over to driver’s side of car so that it is out of the way when removing the manifolds.  Lay the steering shaft on top of the frame rail.  Be sure to lower the shaft before the header is in place.

8. Remove left and right motor mount nuts.

9. Remove nuts holding manifold to head.

10. Jack motor up (make certain NOT to be under the car when doing this and make sure that vehicle is adequately supported!), so that motor mount stud will drop down through aluminum bracket off motor to get enough clearance to remove passenger side manifold from bottom of car.

11. Remove all studs from both heads to allow additional clearance for the installation of the headers.  It may be easier to remove the driver’s side manifold through the top when all the studs are removed. 

1. Install headers up from the underside of the car and bolt in place using aftermarket bolts such as those available from manufacturers such as ARP or Breslin (available from your favorite speed shop) and factory gaskets.  We recommend purchasing a new set of factory gaskets.

2. Reinstall steering rack bolts and motor mount nuts and tighten to factory torque specifications.   

3. Install new O2 extensions – tabs may need to be removed.

4. Unbolt electrical solenoid on driver’s side fender well to gain access to reinstall dipstick tube.  Reinstall dipstick tube and reinstall solenoid.  Reinstall air box.

5. Slip one clamp onto each header followed by the high flow converters or off road pipes.   

6. Install the converter outlet pipes with one clamp on each end.  If you are connecting to the stock exhaust system, or an aftermarket 2 ½” exhaust system, use the supplied adapter stubs from the rear lead pipes to reduce down to the correct size.   

7. Reinstall the factory exhaust system in the reverse order it was removed.  Once all pipes fit properly, we recommend breaking the exhaust apart and using red high temp RTV at each joint to ensure a leak proof seal.  Tighten all clamps making sure that there is adequate clearance.  Reinstall the O2 sensors, using a small amount of never seize on the threads.  Be sure to only apply never seize to the threads-if this is applied to the O2 element it will ruin the O2 sensor.  Connect to the factory harness using the supplied extension harness.  Zip tie the extender harnesses out of the way.

8. Reconnect battery, start car and warm up.  Let cool thoroughly and retighten all header bolts and clamps.  Drive car and enjoy your newfound power.