The Fox Body Mustang is versatile and lightweight. Produced between 1979 and 1993, they had the longest run of any Mustang generation. This makes them pretty easy to find and relatively cheap to buy.
Unfortunately, a significant portion of the third-gen Mustangs were underpowered. Even after Ford added a 5.0L engine, there were mechanical problems that kept the Fox Body from performing the way a Mustang should. Chassis flex led to rough handling, and a restrictive intake and exhaust system choked the engine.
With just a few modifications you can easily correct the Fox Body’s issues. The end result should be a powerful Mustang with a great vintage look.
Whether you’re building a daily driver or a drag-ready Fox Body, horsepower is likely one of your top concerns. Luckily, there are a wide range of modifications that will increase your horsepower.
- Change to Less Restrictive Cylinder Heads
- Add a New Throttle Body and Intake Manifold
- Improve Exhaust
- Install a Cold Air Intake or Hood Scoop
- Swap in a Coyote Engine
Get More Air to the Engine
One of the easiest ways to increase the horsepower of your Fox Body is to improve the airflow. There are a few ways to do this, but one of the most obvious methods is replacing the cylinder heads. The Fox Body had notoriously restrictive cylinder heads. While people used to recommend a GT40/GT40P cylinder head swap, there are many great cylinder head options.
Upgrading the throttle body and intake manifold are two more ways you can improve a Fox Body’s airflow.
Overhaul Your Exhaust System
Getting your Fox Body to take in more air is important, but so is improving how it expels exhaust. When an exhaust is overly restrictive, it can create backpressure. This backpressure prevents your engine from working as well as it should. By improving your Fox Body’s exhaust system, you can reduce backpressure and get more power out of your engine.
Start your exhaust overhaul by replacing the exhaust manifold with long tube or shorty headers. Then, replace everything from the mid-pipes back with a cat-back exhaust system. An axle-back exhaust will help with sound, but won’t do as much for power as a cat-back exhaust will.
Improve Engine Air Quality
While most modifications focus on the amount of air, you can also upgrade the quality of the air for more horsepower. Changing out your air filter for a cold air intake is a great way to get colder, more oxygen-dense air to your engine. Installing a cold air intake shows consistent horsepower improvements and is an easy modification anyone can do.
A functional hood scoop is another way to improve the quality of the air getting to your engine. Plus, they look awesome. In particular, a cowl hood scoop looks particularly striking on a Fox Body.
Do an Engine Swap
If you’re looking to go big with horsepower improvements, and you’ve got a fully stocked garage and wallet, then a Coyote engine swap is a great option. An engine swap gives you the horsepower of a modern Mustang in the lightweight body of a Fox Body.
Handling is every bit as important as power when you’re looking at a build. Fox Body Mustangs excel at being light and versatile. Unfortunately, they also have a reputation for handling poorly that’s well-earned. This is due primarily to chassis flex and some subpar suspension components. Not only are suspension improvements important for drift-ready Foxes, but also for regular driving.
- Upgrade Shocks, Struts, and Other Components
- Install Coilovers
- Add Sway Bars
- Stiffen Chassis
Upgrade Existing Suspension Components
Many people opt to simply replace the stock components with improved versions. This isn’t a bad strategy. Adding stiffer coil springs, adjustable struts, and replacing your soft, rubber bushings for hardier urethane ones is a great start. Your upper and lower control arms are another stock piece that is best discarded in favor of stronger, tubular pieces.
If you’re interested in performance driving, then upgrading from shocks and struts to coilovers is a great idea. Coilovers offer adjustability in addition to improved handling.You’ll be able to easily lower your Fox Body’s center of gravity, which will help with carving corners.
Stiffen the Chassis and Suspension
Front and rear sway bars, also called anti-roll bars, help reduce flex. This makes them a great upgrade for Fox Body Mustangs.
Replacing your K-member is a great way to stiffen up the Fox Body’s suspension, which will in turn improve handling. Which K-member is right for you will most likely depend on what you’re hoping to accomplish. Your k-member will be especially important for drift builds.
Another great way to stiffen up your chassis is by using a subframe connector. A subframe connector will join the front and rear subframes together. This creates a stronger connection and adds stiffness to your Mustang’s unibody design. These are easy to install, and you’ll see the results immediately.
Fixing your Fox Body’s interior might not give you better quarter-mile times, but it will make it more comfortable. It’s no surprise that the Fox Body Mustang’s interior is dated. And unlike classic Mustangs, which look dated in a classy way, Fox Body interiors aged poorly. This is due to an abundance of cheaper plastic parts as well as a lack of modern upgrade availability.
- Upgrade Your Seats
- Install a Short Throw Shifter
- Reduce NVH
- Replace Worn or Broken Parts
Replace Your Old Seats
One of the first interior upgrades most drivers want is new seats. Driving in a poorly padded seat is a real pain in the butt. Thankfully, high-quality drop-in seat replacements are available. If you want to keep your upholstery, you can just upgrade the padding. Adding improvements like lumbar support will make long drives much more appealing.
Install a Short Throw Shifter
For those with a manual transmission, upgrading to a short throw shifter is a modification that will improve every shift. Short throw shifters shorten the distance between your hand and the shifter’s pivot point, resulting in shorter throws.
Automatic transmission Fox Body Mustangs can upgrade to a hammer shifter. While these don’t offer many practical benefits, the ratcheting shift action feels cooler. It looks a lot nicer as well. Just because you don’t shift often doesn’t mean you shouldn’t enjoy every one.
Reduce Noise, Vibration, and Harshness
Noise, vibration, and harshness (or NVH) is one of the main criteria people look for in a vehicle. If you’re out for a drive with a friend, you want to hear them, not the road noise. Adding a soundproofing agent can reduce your NVH. You can also install new underlayment and insulation to cut down on road noise and better control temperatures.
Replace Worn or Broken Parts
Finally, don’t forget to replace any interior parts that are starting to look a little worse for wear. Plastic door handles and locks can break easily, but they can also be replaced easily. Installing a new headliner, dash pad, or center console is fairly easy, but will make a world of difference.
Brakes and Wheels
The Fox Body Mustang’s drum brakes are a sore spot for many enthusiasts. Not only do they lack the stopping power of disc brakes, but they also look and sound cheap. This isn’t helped at all by the original third-gen wheels.
The overly small wheels made the Fox Body look odd and don’t offer the smoothest ride. Changing out your wheels and brakes is a great way to improve your handling, stopping power, and appearance.
- Change to Disc Brakes
- Convert to 5-Lug Wheels
- Adjust Caster and Camber
Upgrade to Disc Brakes
Disc brakes have a lot of advantages over drum brakes. Most importantly, they have much better stopping power. They’re also easier to maintain. Thankfully, upgrading to disc brakes is an option today. While upgrading your brakes, you can also look at upgrading your 4-lug wheels to 5-lug. In addition to being necessary for your brake upgrade, this modification opens up an exciting world of aftermarket wheels.
Change Out Your Wheels
One of the problems with the Fox Body Mustang years was that their stock wheels were a little on the puny side. This made their wheel wells look large and vacant. By adding larger wheels and lowering your Fox Body some, you can correct that look. Caster camber plates should then be added to correct your wheel alignment.
Modified Fox Body Mustangs
It’s no wonder that Fox Body Mustangs have seen a surge in popularity. While their stock power was never noteworthy, a few modifications can make them shine. Not only is it easy to change the appearance of a Fox Body, it’s also easy to improve their performance.
No matter what aspect of your Fox Body Mustang you’re thinking about improving, there are modifications that will help you with your goals.