Ford’s Coyote engine is unusual in its reliability, its efficiency, and its raw power. Mustang fans took to the Coyote instantly.
Car enthusiasts quickly began to work on “Coyote Swaps” in order to squeeze Ford’s modular V8 into the car body of their choice. There are numerous reasons why Coyote Swaps are so popular. It’s an incredible engine with a modular design that allows a great degree of flexibility.
Putting a Coyote Engine into a Fox Body Mustang
Putting a Coyote engine into a Fox Body Mustang is a smart engine swap for a few reasons. The Fox Body Mustang is a popular pick for people who really love to get their hands dirty modifying a car. It’s a great body for modifications, and it’s a light body. Fox Body Mustangs are trim by today's standards and tend to weigh in right around 3,000 pounds, significantly lighter than modern Mustangs.
When you throw a lot of horsepower into a light body, you’re able to get substantially more speed.
The Coyote Engine is one of Ford’s modular engines. This means that it's an overhead cam design rather than a pushrod style engine. Though many pushrod proponents argue that these older-style engines are easier to work on, there's no denying the power and effeciency that modular engines allow for. Additionally, there are still many bolt-on modifications for those who really enjoy working on their engine.
Because Fox Body Mustangs came with pushrod engines changing to a modular style engine means that you’ll need to upgrade several key parts at the same time as the engine. Without these modifications, not only will you not benefit from the additional horsepower, but the engine won’t even fit.
Though these modifications can be challenging, if you’re able to correctly execute a Coyote Swap on a Fox Body Mustang you’ll have 420 horsepower in a 3,000-pound car. It’s worth the effort.
In addition to your Fox Body Mustang and your Coyote Crate Engine, you’ll need a few other parts to make your swap successful.
Parts Needed for a Fox Body Coyote Swap
- An FRPP Control Pack
- Long Tube Headers (optional, but they will fit better)
- A Transmission That's Modular Engine Compatible
- Motor Mounts
- Hydroboost or Manual Brake Set
- Oil Pan
- A New K-Member (Tubular with 4.6 Motor Mounts Preferred)
- Flywheel and Clutch
- Shorter Oil Filter (Possibly)
- Gas Pedal Bracket
Preparing the Fox Body Mustang
First, you’ll need to prepare your Fox Body Mustang for its new engine. The Coyote engine requires more space than the Fox Body’s original engine, so there are some things you’ll need to address while preparing your vehicle for the swap. Even though the displacement might be the same as a 5.0L from the 1980s, physically it’s just a more sizeable engine. This means that some parts of the Fox Body Mustang will not work for the swap.
The Fox Body Mustang’s brake booster will need to be removed. You can either replace the brake booster with a hydroboost setup or use manual brakes depending on how much of a workout you’d like to give your legs.
Though the radiator location for the Fox Body Mustang is in the right place for the Coyote, the Fox’s inlet is smaller. You’ll need to find a way to alter this inlet in order to accommodate the hose. One popular strategy is to weld on a sleeve.
The sway bar in a Fox Body isn’t able to clear the Coyote’s alternator and oil filter. If you plan to keep the sway bar, lowering brackets can be used to lower the sway bar to give the Coyote a little extra space.
K-Member and Headers
The reason why you’ll need a new K-member is that you’ll need more clearance. A tubular K-member is preferred for this reason. You can use short headers or long tube headers.
The Fox Body Mustang's stock exhaust manifold has long been regarded as the weakest part of the entire exhaust system. Upgrading your headers is one of the best and easiest exhaust system upgrades you can complete. It just so happens that doing it right now also makes your Coyote Swap a little bit better.
In this video, Bill from our team shows us how he prepared the engine bay under the hood of his 1996 Cobra for the Coyote Engine. Though some aspects will be different from the Fox Body, this gives a good overview of what a Coyote Swap-ready Mustang body looks like.
The Coyote Engine
Much like you prepared your vehicle for its new engine, you also must modify the new engine for the car. While most of what you need comes in a Coyote crate engine kit, other parts for the swap are sold separately.
If you chose not to replace your K-member and are using the one that came stock with the Fox Body, you will need to make a cut out to accommodate the engine mount on the driver’s side of the K-member. You'll need engine or motor mounts that are compatible with a modular engine.
You will need a different oil pan for the Fox Body. Fortunately, this is a really popular Coyote Swap, so there are a few different oil pans that you can choose from.
Some modders have noticed that the stock length oil filter didn’t clear the sway bar. Others have said it cleared just fine. Different models may have different clearances, but you’ll definitely want to check that out and either replace it with a shorter oil filter or relocate the oil filter.
You should also install your flywheel, clutch, and bellhousing. This is where the modular nature of the Coyote engine becomes a real asset. That said, you will need a longer clutch fork for the Fox Body.
For bellhousing, if you are planning to use your car for racing it’s important to look for one that is SFI approved for your safety. If you're not planning on racing, you have more bellhousing options.
Though you can use the T5 transmission that came stock in the Fox Body Mustang, there are a lot of reasons not to do so. Mostly, you need a transmission that can handle a lot of horsepower. Even the first-generation Coyotes generate 412 horsepower, and the Fox Body was much closer to 225 horsepower.
If you’ve already committed to the speed and power of a Coyote Swap, you owe it to yourself to get a transmission that can handle the horsepower you’ll have on your hands.
You can install a manual transmission or an automatic transmission, the choice is up to you. Even though manual transmissions are more popular with Mustang enthusiasts, there are great options for automatic transmissions that will bolt up perfectly to the Coyote crate engine. In particular, the 4R70W is a popular choice. For manual transmissions, Tremec remains a solid favorite.
The Control Pack
You will need a control pack for any Coyote Swap, and the Fox Body is no exception to that. Though it’s popular with other engine swaps to use a “wrecking yard” setup, that isn’t ever really considered for Coyote Swaps just because the Ford Racing Performance Parts control pack is so good. Ford Performance parts, in general, have a good reputation, and the FRPP control pack does as well.
You will also need a bracket to mount the gas pedal. Even though the control pack comes with a pedal, you'll find that it's not quite right for the Fox's setup. In the mid '80s, car manufacturers converted from cable throttle systems to electronic throttle ones. It's a great upgrade, and it's what the Coyote is intended to work with, but you'll need a bracket to account for the difference in layout.
The one issue the FRPP control pack runs into with retrofit applications though is that the airbox assembly often has difficulty fitting, which can cause the airflow sensor to be set off. Most of the issues deal with placement, and the airbox seems very sensitive to where the MAF sensor is located.
If the MAF needs to be relocated, you will need to retune the PCM.
Bill explains what each part of the control pack does and how to get it working in this CJ’s video.
There are a couple of options here. You can use your existing exhaust with the new headers if it’s in good shape, but you will need a new connector. It’s sometimes more efficient and effective to simply replace the exhaust with a new X or H pipe. Though this involves more upfront cost, it does help to protect your investment.
The Fox Body Mustang’s fuel rails fed from the passenger’s side, but on the Coyote the opposite is true. One solution is to reverse the orientation of the fuel rails. Another option is to use a new fuel line and an AN adapter to work with the fuel rails that exist.
AC and Power Steering
The accessories you’ll need to attach the AC and power steering are hard to predict and vary wildly based on which specific model of crate engine you buy. You will almost certainly need aftermarket brackets to attach either, as well as a power steering hose.
Though it’s a lot of work, there’s a reason Coyote Swaps are so popular and why the Fox Body is such a favorite for modifications. This combination might just give you the ride of your life, and being able to customize it on such a detailed level ensures that your Mustang will be truly yours.
Sources: What Used Car to Buy: 1979-1993 Ford Mustang 5.0, Car and Driver | Six Coyote Engine Swaps You'll Love!, MotorTrend| 5.0 Coyote Modular V-8 Swap Guide, MotorTrend | 1990 LX Is a Coyote Swapped 10-Second Street Car! MotorTrend | 1979 Ford Mustang Brochure, Hemmings