Fox Body Mustang Dual Exhaust Conversion Guide (1979-85)

Created by Jay Walling
Date Created: 2/25/2014
Last Updated: 1/11/2024

We answer all the common questions about doing a dual exhaust conversion on early model Fox Body Mustangs! This guide will help you give your Four-Eye Stang that iconic and aggressive exhaust tone you have been dreaming about!

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Nothing makes your Fox Body Mustang look and sound more like an American muscle car than a dual exhaust system. Unfortunately the 1979-85 Mustangs did not come with a true dual exhaust system from the factory. That doesn’t mean you have to go without a dual exhaust on your early model Fox Body Mustang.

In this article I will be covering some of the most common questions we get about converting Fox Body Mustangs to dual exhaust. So if you are thinking about a dual exhaust conversion on your Four Eye Mustang – this will help get you started! Let’s take a look at the most common questions we get about these Mustang dual exhaust conversions.

What Parts Do You Need For A 1979-85 Mustang Dual Exhaust Conversion?

The following is a simplified list of components you need to convert your early model Fox Body Mustang to a true dual exhaust system. Below you will find a more detailed list of tech tips for every year model. Certain year ranges require slightly different steps. This is just a simplified list of parts you will need for the Mustang dual exhaust conversion:

  1. 86-93 Mustang H or X Pipe
  2. 79-85 Mustang Dual Exhaust Hanger Kit
    • (1) Mid-Pipe Hanger for Manual Transmission
    • (2) Muffler Hangers & Brackets
    • (2) Tail Pipe Hanger Brackets
    • (2) Tail Pipe Hangers
  3. 86-93 Mustang Cat-Back Exhaust Kit

What is needed to complete a dual exhaust conversion on my 1979-85 Mustang?

Depending on what year model you are looking to convert there are just a few simple things to remember when starting a dual exhaust conversion. Let’s start with the 1985 Mustang since it is the most unique one out of the group.

The 1985 Mustangs had a unique dual exhaust system that started with a “Y” into a single catalytic converter and then into another “Y” back out to a dual exhaust cat-back similar to 86-93 models. The 1985 Fox Body Mustangs simply need a double-hump transmission crossmember to convert to a conventional X or H pipe from an 86-93 Mustang. Once the double hump corssmember and mid-pipe are installed, you can simply install the 86-93 cat-back exhaust system of your choice.

The 1982-84 Mustangs all had single exhaust. They require the same double hump crossmember plus hangers for the mufflers and tailpipes. I do want to point out that the rear brake hose is in close proximity to the right muffler and you need to keep it protected. The most tried and true method is to adjust the muffler so that it doesn’t touch the hose. See our complete list of muffler and tailpipe hangers below! Once the crossmember and mid pipe is installed you can simply install the 86-93 Mustang cat-back exhaust system of your choice. To take all the guess work out of selecting the right hangers be sure to pick up the 5.0Resto Dual Exhaust Hanger Kit.

Fox Body Mustang Dual Exhaust Conversion Guide (1979-85) - Fox Body Dual Exhaust Conversion

The 1979-81 Mustangs are the same as the 82-84 models expect that the brackets that hold the double hump crossmember are narrower. This will require you to do some modification for the Ford Racing or factory double hump crossmembers to fit. If modification isn’t really your thing, I would highly recommend the Stifflers 1979-81 Mustang Transmission Crossmember (STF-TCBM06). It was designed specifically for these year models and requires no modification for installation!! Once you have the crossmember and mid pipe installed you will need put pick up a 86-93 cat-back exhaust of your choice along with our muffler and tailpipe hangers (see below).

All 1983-85 fuel injected Mustangs have trouble running dual exhaust because of the location of the frame-mounted fuel pump. It sits where the muffler wants to reside on the passenger side. Most Fox Body enthusiasts solve this by using a smaller muffler to give some extra clearance.

Do 1986-93 Headers Fit My 1979-85 Fox Body Mustang?

Yes! All 86-93 headers, both shorty style and long tube, will fit 79-85 Mustangs; however, they will not have the provision for the factory heat riser. You must remove it to finish off the header installation. The hot air tubes from the headers to the dual snorkel air cleaners are also not fitted to 86-93 air cleaners. Beyond these simple modifications all 86-93 headers are a direct bolt on for your early model Fox Body Mustang. Be sure to check out our full line of headers here: Fox Body Mustang Headers.

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About the Author

Jay has written content for Late Model Restoration for over 10 years, producing over 120 articles. Jay has an extensive 25-plus-year background in automotive and is a certified Ford Technician. Read more...
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