Free Shipping On Orders Over $75. Details

Talk to a Mustang Enthusiast
M-F 9A-11P, Sat-Sun 9A-9P
Win $6,000! Enter Daily >

Best Sellers

How to install a SLP Power-Flo Catback Exhaust on your 1999-2004 GT Mustang

Installation Time

2 hours

American Muscle
Shop Parts in this Guide



Item #QuantityPart NumberDescription
1.1310304795Driver-side Intermediate Pipe
2.1310304796Passenger-side Intermediate Pipe
3.1310304797Driver-side Over-axle Pipe
4.1310304798Passenger-side Over-axle Pipe
5.2308560782PowerFlo Muffler (M31004)
5.2310013919Loud Mouth Resonator (M31007)
5.2310013818Loud Mouth II Muffler (M31007A)
6.1310304792Driver-side Tailpipe
7.1310304791Passenger-side Tailpipe
8.2310305785ATailpipe Tip
9.2307334788Ball Flange
10.83081443802.5 in. Exhaust Clamp

Warning: SLP recommends allowing the vehicle to cool (not running) for five hours before beginning the installation. SLP recommends wearing safety glasses for the complete installation.


1. Raise the vehicle to allow for a sufficient work area underneath the vehicle. A vehicle lift will make this installation much easier, however, raising the vehicle can be accomplished using ramps or a jack with jack stands.

2. Remove the old exhaust from the vehicle by unbolting the 2 flanges from the H-pipe and removing the exhaust hangers from the rubber insulators.

Note: You may need to cut the old pipes in the vicinity of the rear axle or disconnect the shocks to gain enough suspension clearance to remove them.

3. Place the ball flange of the driver side intermediate pipe (shorter of the two) onto the driver side hpipe outlet, slide the flange into place over the studs, and loosely tighten the nuts.

Note: Tighten all clamps and fasteners just enough to hold them in place. Leave them loose until the end to allow adjustment.

4. Place one of the supplied band style exhaust clamps onto the inlet of one of the resonators (PN M31007) or PowerFlo mufflers (M31004) or Loud Mouth II mufflers (PN M31007A). The inlet side is easily identifiable because it is larger and slotted. Slide the inlet of the resonator or muffler over the end of the driver side intermediate pipe and loosely tighten the clamp. The PowerFlo mufflers are the same for the driver and passenger side but the outlets must be angled away from the center of the vehicle for the system to fit properly. If one of the outlets is angled inward just turn the muffler over.

5. Slide another exhaust clamp onto the inlet of the driver side overaxle pipe, place it over the axle, and slide it onto the resonator or muffler outlet. Now insert the hangers on the overaxle pipe into the rubber insulators on the vehicle underbody. Loosely tighten the clamp.

6. Place another exhaust clamp on the front of the driver side tailpipe and slip it onto the overaxle pipe. Loosely tighten the clamp.

7. Again, slide an exhaust clamp onto the end of one of the tailpipe tips, slide the tip onto the tailpipe, and slide the hanger into the factory tailpipe hanger. Loosely tighten the clamp.

8. Repeat this entire procedure (steps 3 through 7) for the passenger side.

9. Now adjust all the pipes until the tips are located as desired and all the pipes have enough clearance from all suspension, brake lines, fuel tank, driveline, and body parts.

10. Tighten all the clamps and fasteners working from the H-pipe back, while checking and maintaining correct tip location along the way. The H-pipe flange studs/nuts should be tightened to 26 lb/ft.

11. Start the vehicle and inspect for leaks.

12. Double-check all fasteners and clearances after test driving. Adjust as necessary

Best Sellers