How To Install a Flowmaster American Thunder Catback Exhaust on Your 1987-1993 Mustang GT

Before:

Step 1:
For easier removal of the stock exhaust saw the tailpipe apart from the muffler about 2” behind the muffler. This does not need to be done but will make the removal process less of a headache.

Step 2:
Remove the tailpipe from its hanger at the rear of the vehicle. Lubricant can help the process. Repeat for both sides.

Step 3:
Support the mufflers and then remove the muffler from the hangers. Lubricant can also help this process.

Step 4:
Remove the two lugs on the flange that connects the mufflers to the midpipe (about 18 inches toward the engine) Remove the old mufflers. Clean the bolts if necessary.

**Each muffler and tailpipe goes on a certain side**
Part #942548-183 (muffler) and #16219 (tailpipe) goes on the right side of the vehicle
Part #942548-182 (muffler) and #16218 (tailpipe) goes on the left side of the vehicle

Step 5:
Line up the new muffler with the old flange and reconnect using the old lugs (or new 3/8” one if the old ones are rusted/stripped).

Step 6:
Next reinstall the new muffler to the muffler hanger. Repeat for both sides.

Step 7:
Fit the correct tailpipe over the rear axle of the vehicle. Spray with WD-40 for ease while fitting the tailpipe into the muffler.

Step 8:
Position the tailpipe so that there is ½” clearance between the tailpipe and the chassis and axle. Hang the tailpipe onto its hanger at the rear of the vehicle. Repeat for both sides

Step 9:
Install the provided hangers (u-clamp) onto the tailpipe-muffler connection and tighten only when the tailpipes are in the correct position. Make sure all connections are secure and all hangers are attached properly.

Step 10:
Install the provided hanger keepers onto each hanger. Start your Mustang and hear the roar.

After:

Installation Instructions written by AmericanMuscle Customer Nick Bourquin 12.23.2014