How to Install a Flowmaster American Thunder Catback Exhaust on Your 1987-1993 Mustang LX, 1986 Mustang GT

This Mustang Parts Installation Guide Works For

Flowmaster American Thunder Catback Exhaust w/ Polished Tips (87-93 LX; 86 GT)DOWNLOAD PDF

Tools Required

Installation Time: 2 Hours

Installation

Removal:

  1. Using a hacksaw or sawsall, cut the stock tailpipes off, approximately 2” behind the muffler case. Separate the steel tailpipe hangers from the rubber mounts at the rear of each tailpipe. A lubricant may ease removal. Remove the stock tailpipes from the vehicle.
  2. Support the stock mufflers with stands. Separate the steel muffler hangers from the rubber mounts at the rear of each muffler. A lubricant will usually ease removal.
  3. Remove the two nuts at the muffler to catalytic converter flange connections. Remove stock mufflers from the vehicle.

Installation:

  1. Before installing anything, prep the clamps supplied in the hardware kit by removing the outstand applying a thick lubricant such as white grease or anti-seize to the threads.
  2. Position muffler#942548-183into the stock location, on the right side of the vehicle. Slide the flange on the pipe up to the flange on the head pipe and reinstall the stock nuts onto the studs. Connect the hanger rod at the rear of the muffler to the rubber mount on the vehicle. Repeat this step with muffler#942548-182on the left side of the vehicle.
  3. Slip the FLOWMASTER right side tailpipe #16211 over the axle and into the right muffler outlet. Slide tailpipe hanger-rod into the stock rubber hanger at rear of the vehicle. Install a 2 1/2”clamp and tighten enough to hold in place but still allow for adjustment. Repeat this step on the leftside of the vehicle using tailpipe#16210.
  4. Adjust tailpipes for proper alignment and tighten all connections. Maintain a minimum clearance of 1/2” between the drivetrain and all chassis components. Slide the provided 7/16” hanger keepers onto the ends of the hangers located at the rear of the mufflers and tailpipes. Slide them up to the rubber mounts to securely hold the system in place.
  5. 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.
Flowmaster-American-Thunder-Catback-Exhaust-(87-93-LX-86-GT)

Packing List

QtyPartPart # or Size
1Muffler assembly, Right942548-183
1Muffler assembly, Left942548-182
1Tailpipe, Right16211
1Tailpipe, Left16210
1Parts KitPK342
22 1/2" Horseshoe clampsMC250S
47/16" hangers keepersHW5021