How to Install Flowmaster American Thunder Cat-Back Exhaust - Middle Side Exit (99-03 Lightning) on your Ford F-150

1) Support the muffler with a stand of some type and using a 15mm wrench loosen the clamps holding inlet pipes behind the catalytic converter.

2) Separate the three hanger rods from the rubber mounts on the vehicle. (A lubricant will make this easier.)

1) Before installing anything, prep the clamps supplied in the hardware kit by removing the nuts, and applying a thick lubricant such as white grease or anti-seize to the threads.

2) Take two of the #MC250S clamps provided in the parts kit and slide them onto the inlet pipes. Slide the muffler assembly #9525554-172 onto the back of the catalytic converter and slide the hanger rods at the rear of the muffler into the rubber mounts on the vehicle.

3) Take the other two #MC250S clamps and slide them on the outlets of the muffler assembly. Take exit pipe assembly #16412 and slide into the outlets of the muffler assembly. Slide the hanger rod on #16412 into the rubber mount on the vehicle. Tighten clamps enough to hold, but still allow for adjustment.

4) Take the two stainless tips #ST339 and slide them onto the back of the exit pipe assembly #16412. Adjust and rotate to your desired location, and tighten clamp bolts on the tips to hold in place.

5) Adjust the position of all muffler, pipes and tips to provide a satisfactory fit. Maintain a minimum of 3/4" clearance between the Flowmaster system, the drivetrain and chassis components, while also keeping suspension travel and vibration in mind.

6) Tighten down all clamped connections securely. After the system is secure, slide the 7/16” hanger keepers onto the muffler assembly and exit pipe assembly. This will prevent the hangers from slipping out of the rubber mounts.

7) For a cleaner appearance and more secure installation, we highly recommend welding all slipfit connections. If you live in a geographical area that has harsh winters or sees a great deal of precipitation, the use of high temperature paint over the welded areas can help to prevent surface rust and premature corrosion.