Mustang ARH Stainless Long Tube Headers (1999-2004) Installation Instructions
1999-2004 Mustang ARH GT/Bullitt 1-3/4"Long Tube Headers with 2.5" Stainless Steel Off-Road X-Pipe
These Stainless Steel 1-3/4" Long Tube Headers with a 2.5" Off-Road X-Pipe from American Racing Headers for 1999-2004 Bullitt Mustangs and Mustang GTs.
American Racing Headers long tube header system for 1999-2004 2V Mustangs are manufactured from 304 stainless steel and provide great fit and big horsepower and torque gains throughout the RPM range. Features a one piece design and 1-3/4 inch primaries to accommodate both normally aspirated and supercharged applications.
These Stainless Steel 1-3/4" Long Tube Headers with a 2.5" Off-Road X-Pipe from American Racing Headers for 1999-2004 Bullitt Mustangs and Mustang GTs.
American Racing Headers long tube header system for 1999-2004 2V Mustangs are manufactured from 304 stainless steel and provide great fit and big horsepower and torque gains throughout the RPM range. Features a one piece design and 1-3/4 inch primaries to accommodate both normally aspirated and supercharged applications.
Tools Required:
- Jack Stands (5 or more)
- 1 Jack
- Ratchets, Sockets, Extensions, and Swivel
- Impact Gun
- Wrenches
- O2 Socket
- E8 External Torx Bit
- Pliers
Install Difficulty:
- Difficult Project
1. To begin installing your new Mustang American Racing Headers MSTE2V34NC 1-3/4 inch Long Tube Headers, review the parts and make sure that all of the components are there.













2. Remove the negative Mustang battery cable and loosen the lug nuts on the front wheels.

3. Raise the car as high as possible on all sides and support it using jack stands on the frame rails. You will need room to remove the Mustang K-member and to install the headers.
4. Remove all four Mustang oxygen sensors, along with the H-pipe or X-pipe.

5. Remove the Mustang front brake calipers and support the caliper. Do not let the caliper hang by the brake hose.

6. Remove the Mustang driver's side ABS sensor and the Mustang passenger's side ABS sensor.

7. Remove the Mustang sway bar endlinks and make sure your steering wheel is locked. Then, disconnect the steering column from the rack. The easiest way to access this is from underneath the K-member on the engine side.

8. The steering rack will stay attached to the K-member, so the power steering lines must be disconnected. Remove the pressure line and the return line.



9. Plug any open lines.

10. Support the front lower control arms with a jack so you can remove the top Mustang strut nut. Once the nut is removed, slowly let the jack down. Be careful, as the spring is under pressure.



11. Remove the two rear Mustang K-member brace bolts.

12. Next, support the Mustang engine. I used an engine support bar and put a jack stand under the transmission. You want to put the jack stand under the engine, but I didn’t have the car high enough. So, I got it as close to the front of the transmission as possible. There are very few places to bolt the engine support bar. I used two studs that come out of the timing cover.


13. Support the K-member with a jack.
14. Once everything is safely supported, you can remove the two nuts that mount the engine to the K-member. Then, remove all eight K-member bolts and drop it from the car. Two of the bolts are on the rear of the K-member, on either side. There is one in front of the Mustang springs, and one behind the springs. The front four stick through the frame rail. Be sure not to lose the nuts.



15. Next, remove the Mustang motor mounts from the engine. There are two nuts on the driver's side that hold the ground on, while the starter bracket is on the passenger side. Then, remove the three bolts holding the motor mounts to the engine.

16. Remove the bolt holding the oil dip stick tube to the engine.

17. Loosen the nut that holds the EGR tube to the exhaust manifold on the driver's side.

18. Remove the three bolts holding the Mustang starter to the bellhousing.
19. Now, you can take off the stock exhaust manifolds. Some studs may be stuck in the cylinder head, which can be removed once the exhaust manifold is taken off.
20. Remove the oxygen sensors and install the Mustang oxygen sensor harness extensions. You’ll most likely have to cut off the tabs to fit the connectors together.


21. Remove the Mustang oil dip stick tube. It’ll probably be a pain and require a pry bar and a hammer. I had to buy a new oil dip stick tube.

22. The Mustang long tube headers are ready to be installed. I started with the passenger side. The American Racing Headers come with grade eight bolts. You’ll need various tools to install these. Most of the bottom bolts can be reached with a 10mm socket, extension, and ratchet. All of the top bolts (except the front) must be reached with a wrench. A stubby wrench will make things much easier. I used blue Loctite. Start all of the top bolts and slide the headers into place. Then you can start the bottom bolts. Start all of the bolts before tightening any. Some of the header tubes may be in the way of the bolts.







23. Install the starter.

24. Install the Mustang passenger's side motor mount. The starter wires tuck underneath the bottom of the motor mount, so set them in place before tightening the motor mount. Then install the starter wire bracket on the motor mount stud.

25. Before you install the driver’s side header, you will need to tighten the EGR tube to the headers. There is no room to tighten the nut with a wrench once the headers are installed. I had trouble lining up the EGR tube, so I unbolted the Mustang EGR valve from the engine.

26. Install the driver's side headers just like the passenger side. After putting in the top bolts, first install the second bolt from the front. The primary tube really gets in the way of the bolt if you don’t install it first.



27. The oil dip stick tube can now be installed and should be spaced away from the header.




28. Install the oxygen sensors and zip tie them safely back from the Mustang exhaust. Use anti-seize on the threads.

29. Now, you can re-install all of the front suspension. The rear K-member brace will not fit with the long tubes. Once the suspension is installed and the motor is tight, you can install the Mustang X-pipe. You can coat the slip fittings with anti-seize in case you need to remove the exhaust at a later time.

30. Installation of your new Mustang American Racing Stainless Steel Long Tube Headers is complete!