Hey, it’s Terry!
Photograph Courtesy Voshlag Motorsports
“It is, bang for the buck, one of the best cars for the money,” says Terry Fair of Vorshlag. “I compare it with the C5 Corvette, which is a good performer for the money. Unlike the C5 Corvette, it’s much newer and it fits people taller than 5-foot-9. Nothing else compares for that price range.”
If height or money isn’t an issue, the S197-chassis Ford Mustang offers other benefits.
“It’s got great visibility in all directions,” he continues. “It comes with a good V8, a decent six-speed transmission, and an indestructible rear axle. You can get it with good brakes, too. It’s a good platform because you can beat the snot out of it and it takes it. The Mustang doesn’t fall apart like the Camaros of that time. Plus, there’s a lot of aftermarket support.”
Okay, if that sold you, then let’s dive into the ideal S197 Ford Mustang? (Yes, there are models to avoid and easy mods that make the S197 even better.)
For this story, we’re going to focus on the non-Shelby editions of the S197. Surprisingly, that doesn’t narrow the field down much. There’s the 3.7-liter V6, 4.6-liter V6, 4.6-liter V8, and the 5.0-liter V8.
“Ignore the V6 cars,” Terry interjects. “It’s terrible in every way–significantly down on power, comes with awful suspension, tires and brakes. You have to do so much to make a V6 perform.”
Okay, we’ve halved the number of choices. How about the 4.6-liter V8?
“The 4.6 is appropriate only if you’re building for a class, such as NASA American Iron,” says Terry. “It’s a bit underwhelming by today’s V8 pony car standards, but it is at least reliable They never make more than 352 horsepower, and that’s with a lot of work. It’s pretty hard to justify as it’s not that big of a savings when compared to a 5.0.”
There’s something about a 5.0 in a Ford, isn’t there? That holds true with the S197.
Photograph Courtesy Vorshlag Motorsports
The Coyote 5.0 came in the GT (2011-’14) and Boss 302 models (2012-2013). Depending on which one you get, Ford rates the 5.0 for 412 to 444 horses, and that’s stock.
As far as transmissions, opt for the six-speed Getrag/Ford MT82 manual. “We tend to avoid the six-speed automatics of that era,” as Terry says, “they tend to run hot on a road course when you get fast, and are geared somewhat poorly.”
The MT82 isn’t exactly indestructible, though. “As long as you’re not trying to drag race or powershift everything, the MT82 is appropriate for that power level that it came with,” adds Terry, “but not a lot more.”
To sum it up, “I only push people toward the Coyote, 5.0-liter V8, six-speed manual cars,” he says. “I know that’s narrowing out 80% of the cars out there, but you’re saving yourself loads of hassles.”
Perhaps you’re perusing Facebook Marketplace for a 2011-’14 GT or a 2012-’13 Boss 302 with a 5.0 and a six-speed as we speak. Before you reach out to that seller, there are a few other things you should know.
Despite being a 10-year-plus-old car, the S197 ages well. With proper care, Terry says they should last 200,000 miles no problem. If you want to participate in motorsports, obviously, avoid the convertibles.
Now, let’s talk details. “The 2011 model year was the first that Ford put in electric power steering,” says Terry. “It can have some problems if you do modifications that confuse it. For example, when we changed our front lower control arm bushings to polyurethane, it caused a weird steering shutter. To fix it, you have to get an EPS reprogrammed by Ford. We have since found that if you replace the rack with one from a 2012 to 2014, it will solve this.”
Ford offered different brake packages for the S197.
“Look for a car with Brembo brakes,” he says. “For 2011 to 2012, it was an option. Then, they made a Track Pack Mustang for 2013 to 2014, and it also came on the Boss 302. The package includes 14-inch rotors, with four-piston Brembo calipers. It’s a big upgrade over the base rotors and calipers, and the 14-inch Brembo setup is the bare minimum you want for track use. But these brakes are very easy to add. If you find a non-Brembo car, just budget for this upgrade before you get to the track.”
In fact, the Boss 302 and Track Pack Mustangs have other perks.
Photograph Courtesy Ford
“They all came with a Torsen differential,” Terry says. “It becomes required after a certain point. The regular GT and early Brembo cars came with a clutch-style differential, and those wear quickly. We got to where we were running 315-inch-wide Hoosier tires and had a little more power, and we couldn’t get a weekend out of a set of clutch plates, even the upgraded carbon ones. They just ran super hot.”
Lastly, Ford offered 3.31:1, 3.55:1 and 3.73:1 final drives.
“The Track Pack and Boss 302 cars came with a 3.73 final drive, and it was awful,” says Terry. “It didn’t work with the transmission ratios. In autocross, second gear runs out at 55 mph, which is terrible. On track, you have to use third, fourth and fifth a lot. We took 3.55 and 3.73 final-drive cars and put a 3.31 in it and it solved that. We could run second gear to 70 mph and used third and fourth gears at tracks instead of third, fourth, fifth. It’s not a big thing to fix, though. You can get a 3.31 final drive from the aftermarket for $180 to $200, and it’s easy to change. But, know what you’re working with.”
The Boss 302 offers another bonus.
“The Boss 302 was the first Mustang that Ford certified in a 12-hour endurance test on track,” Terry says. “The cooling system, the brakes, the transmission, the differential could last 12 hours of hardcore abuse.”
Track Pack cars are fairly rare, as is the Boss 302, but Terry says what they came with is easy to replicate.
Terry says Mustangs are fairly reliable and sporty out of the box, but they still can use some improvement, even for autocross or an occasional track day.
At the bare minimum, aka phase 1, Terry recommends camber plates, tires, brake pads and fluids. There is no factory camber adjustment, so adding front camber goes a long way, says Terry. Decent performance brake pads are a must for track use, as the soft and quiet OEM versions wear down quickly on track. But, ultimately, if you’re looking for easy speed, wider wheels and tires are your answer.
“Nothing will make for a bigger drop in lap time than going to a wider wheel and a bigger tire,” he says. “The Brembo and Boss 302 Mustangs didn’t come with a lot of wheel and tire, with a 9-inch wheel up front and a 9-½-inch in the rear. Luckily, they can fit a tremendous amount of tire. These cars can fit an 11-inch wheel, with different offsets front to back, or with a spacer. An 18x10 will fit front and back, without any spacers, but it looks funny because the axle widths are different front to back. There’s an 18x10 that fits a 275 to 285 tire, which is a huge upgrade over the stock 255. We generally do a 19x11 with a 305/30R19 or an 18x11 with a 315/30R18.”
If you’re a serious autocrosser or want to track your car often, then you need to start at phase 2. This focuses on making the handling more suitable for motorsport rather than just everyday cruising. The first step is to address the ride height. Terry strongly advises folks to not go with just any lowering kit, though.
“These cars sit up high from the factory,” says Terry. “A lot of people go with lowering springs, which does improve looks, but they aren’t much stiffer–about 10% to 30% stiffer. These soft rates still allow a lot of brake dive, squat, heave and roll. The car moves around a lot because they have soft factory springs, starting around 110 lbs./in. on the front. Lowering springs don’t fix that but they do lower the center of gravity.”
Keep in mind that when you lower any car, it changes the suspension geometry. That means you need to make more changes than just lowering springs.
“Over-lower the rear, without changing the lower control arm geometry, and it makes the cars skittish as they start to have anti-squat problems,” he says. “Then you need to cut the axle-mounted rear bump stops. Cut them in half, to start with, or the rear will bottom out on bigger bumps.
“You also should install an adjustable-length rear Panhard bar, or the entire axle shifts to one side when you lower the rear ride height. Add a lower control arm relocation bracket in the rear to fix the anti-squat geometry. So, that’s $100 to $150 for the set of brackets and about $150 for the adjustable Panhard bar. Do these things and you lower the rear safely an inch and a half.”
Going back to specific components, Terry says be careful of which struts you replace the stock ones with.
“When you lower the front of these cars, you lose all of that amount in bump travel, if you’re using the stock-length struts,” says Terry. “Anything that isn’t an aftermarket coil-over is almost always the OEM length. We found a certain Bilstein monotube housing that’s an inch shorter than stock. So, we couple our camber plates, a choice of moderate lowering springs, and this particular shorter Bilstein strut and shock. It’s currently $1950 for the entire package, preassembled and ready to install.”
Don’t forget the rear, either.
“When you lower these cars, it changes the pinion angle,” Terry says. “Adjustable upper and lower control arms can get the pinion angle back to a 2- to 3-degree down angle, and it helps with off-the-line traction and slow-speed corner exit, especially in autocross.”
Admittedly, this change does not adequately address the spring rate issue, but it does help with the stance and center of gravity.
Also, if you don’t have a Torsen diff, it’s time to install one. An aftermarket one is relatively inexpensive and so are the gears.
“Everything is so plentiful with these cars,” says Terry. “You spend $200 on gears and $300 to $400 on a differential. That’s super inexpensive compared to almost any other car–a Corvette, Subaru, BMW–where you spend thousands of dollars to do what you can do with a Mustang for hundreds.”
Lastly, Terry moves up to an 11-inch wheel, if you hadn’t done so already, and adds brake cooling measures.
Okay, now you want a serious track car. It’s time to address those spring rates.
“Coil-overs are the biggest change you can make, lap time-wise,” Terry says. “On a two-minute track, you usually see a 2.5 second drop. We typically start at 450 lbs./in. springs on the front, 175 lbs./in. springs on the rear.”
Then take a look at the bushings. “We start with coil-overs and lower control arm bushings, because they’re squishy,” he says. “A lot of people put polyurethane bushings in the upper and lower control arms. However, because it’s a three-link rear, as the axle articulates, especially when you go over curbing on one side, the whole axle has to pivot relative to the car and poly bushings don’t pivot. It makes the rear suspension bind and unstable.
“People will go straight to spherical bearings. That’s terrible for the street. They’re at the bottom of the car and get sprayed with water and dirt–and they wear out quickly and clunk and bang around. You can get away with spherical bearings on the upper arm, because they’re further away from the spray of dirt and grit.
“There are not many good solutions. The only bushings that we’ve liked, and weren’t noisy, were dual-durometer elastomer bushings. Otherwise, we tell people just leave the stock stuff in there.”
Reconsider your rear brakes, too.
“At this stage we would like to upgrade the 11.25-inch-diameter rear rotor to the 13.8-inch GT500 version, which uses the same single-piston sliding caliper as the GT. The caliper needs to be remounted with the longer GT500 brackets, or one of the aftermarket options,” says Terry. “You’ve now got a rear rotor that’s bigger, but it’s not necessarily to add more stopping power, but more thermal capacity. What we’ve found is on a cold day you can often thermally shock the small OEM rear rotors when you come off track, and they can split. The larger GT500 rears last much longer and don’t seem to pop from thermal shock.”
Photograph Courtesy Ford
But don’t touch the anti-lock brakes.
“The S197 has one of the best ABS systems we’ve seen,” Terry says. “That 2011-’14 system is what we swap on other cars.”
Cooling, not only the brakes, but the engine becomes a bigger factor as you go faster. Terry recommends going with one of the many aftermarket radiators, which sell for a few hundred dollars and offer much greater cooling.
An external oil cooler might be a good idea, too, but don’t keep the one that came with the Boss 302 Track Pack car.
“It’s really a preheater for the oil,” Terry says of the OEM oil cooler. “Take that off and put an aftermarket one on. That gets rid of the coolant-based preheating and has a thermostat-controlled external oil cooler, which makes these cars bulletproof.
If it’s a muscle car, it should have some muscle, right? Well, the Mustang comes with plenty, so don’t touch the 5.0, especially if you haven’t done any other mods, yet.
“People want to modify engines and add power first when they come with a 255 tire and with 380 horsepower to the wheels,” he says. “That’ll just fry the tire.”
In fact, Terry strongly discourages internal engine work.
“We beat the snot out of an S197 for five years,” Terry says. “It had 19,000 miles, all on track or autocross. If you don’t overrev it beyond 7000 rpm or do internal engine mods, the engine lasts forever.”
However, bolt-on mods, such as a cold-air intake and headers, can provide some sizable gains and shouldn’t hurt the engine.
“The factory airbox is restrictive–add a cold air intake, and with a tune that’s 10 to 15 more peak horsepower,” says Terry. “The factory exhaust header is very restrictive. A free-flowing 1-7/8-inch primary long tube exhaust header and mid exhaust picks up a lot, even with catalysts. On my 2011 GT, the headers picked up 35 peak horsepower, and 60 to 70 wheel horsepower in the middle rpm range. There is no bigger, safer power addition than the exhaust.”
Of course, when you add headers and a cold-air intake, you got to retune it, but take care in who you bring your S197 to.
“Work with a tuner who knows the kind of driving you’re doing,” Terry says. “We had to train drag racing shops to tune these conservatively and not run too much timing. On a road course you’re spending 60% to 70% of the time full throttle, and that’s way more abuse than a drag racer will do in a weekend. We do a progressive throttle map so a small foot change doesn’t make a big change at throttle.”
If you’re thinking of supercharging, Terry says to stop right there.
“Adding a supercharger doesn’t make these engines more reliable, but in fact does the opposite,” he says. “High inlet air temperatures, plus elevated coolant and oil temps, will significantly shorten your track sessions–and possibly the engine’s lifespan. It’s just physics.”
If you’re making more power, once again, don’t forget to upgrade the cooling. Also, you might want to consider going with an aftermarket transmission, too. Tremec offers a kit that’s a bit more robust than the OEM version.
“The aftermarket is full of wallet-lightening parts, and many simply don’t do anything beneficial,” says Terry. “I’m not saying you should buy only from our company. There are a lot of good suppliers out there, but there’s also a lot of bad actors.”
First example, torque arms.
“Why?” asks Terry. “This is a 1960s solution for a 21st century car. The S197 already has the best modern solid-axle rear suspension ever built, with an effective three-link plus Panhard design. A torque arm just adds a lot of its own problems”
Think you need to stiffen the S197? Think again.
Photograph Courtesy Ford
“These cars don’t need any additional chassis bracing, in any form,” he says. “They’re already a rolling tank. It’s one of the stiffest, most torsionally rigid cars Ford had ever built, only to be surpassed by the S550.”
Many view Mustangs as heavy machines. However, getting them lighter doesn’t come easy.
“Generally, when we lighten these cars to cage them, we can get about 250 pounds out,” says Terry. “Just under 3500 pounds is where they get before you gut them. As long as you can run a 315 to 305 tire, weight is not that big of a deal. You can keep up with a lighter car with a similar tire-to-weight ratio, and you’ve likely got better brakes and more power to pass them on the straights.”
Ultimately, when it comes to the S197 Ford Mustang, Terry reminds you to not take big swings. “It’s all these little things we do that add up to a big difference,” Terry says.
Hey, it’s Terry!
Fair is awesome--miss seeing his posts since the demise of the pro-touring movement . . .
Well I wasn't shopping for S197 Mustangs but now I have a new car to put in my marketplace watch list. I always liked the look of the Boss 302 cars.
I love S197's - they're one of the best bang for buck cars out there, and they're easily the best option for us tall folk (I'm 6'5").
Something that is underrated are how cheap parts are. I bought reman'd S550 6-piston Brembo calipers from Motorcraft for $250 each (seriously - LINK and LINK) - those paired with GT500 rotors gives you MASSIVE brakes for minimal cost. Seriously, look at these things...
Suspension is easy with tons of options, they're modern without being overly tech-y, and frankly, they aren't that heavy compared to other modern cars. 3500lbs these days is nothing out of the ordinary. They fit tons of tire (I was previously running 11" wheels with 305 square tires), and they're really reliable. Mine I turned into an "RS" style build, with Boss 302 Recaros (awesome seats) and the LS rear seat delete. It's the perfect dual duty weekend car that you can occasionally take to the track.
There's some benefits to the 13-14 over the 11-12, and newer tends to be better if you don't mind the looks. The track pack is better than the Brembo pack on the earlier cars, and the Recaros are some of the best factory seats that I've been in. The S550 is a better car, sure, but for the price, it's tough not to love the S197.
Biggest downside - the constant Mustang crowd jokes from your friends.
TL;DR: You should buy an S197
I'll add if you are not into being competitive and just want a solid dual purpose road and track car don't overlook the 4.6 cars. I personally think the 05-09 looks better, they are marginally lighter, reliable and sturdy.
I'm right at that that 330WHP limit of reliable performance with out a supercharger or wild cam. Added the GT500 brakes, Torsen, springs dampers, bars, etc made a solid and fun ride.
There are two camps on suspension on these, stiff springs and softer sways or stiff sways and softer springs, I went with the latter for ride comfort. GT500 wheels are 9.5 wide, relatively light and cheap, next step for me are some 18 x 10 or 11's.
In reply to rustomatic :
Did the pro touring movement die? I didn't notice.
We're still doing plenty of S197, S550, and S650 Mustang development these days. :)
My 128i was objectively the better car... But I liked, enjoyed, and miss my 4.6 S197 more. I have little interest in any more BMW's, but would definitely be open to getting another S197.
Hello Terry!
Always enjoy your posts on TMO. You camber plates are next on my list. Drilled out the shock towers last weekend.
My comments about the 4.6L 3V engine come across as a bit harsh. These engines that came in the 2005-10 GT aren't bad, just down 100 hp over the Coyote cars.
With the right mods they can still be competitive. One of my former employees Jon B had this 2006 GT and added MCS coilovers, 18x11" wheels, 315mm tires, and a handful of the other mods we mentioned in JA's article. He dominated CAM-C class locally for an entire season, winning every event in Texas Region SCCA. He even ran well in Optima with it.
This was the same car before the coilovers - with popular lowering springs and the K-branded adjustable dampers. Well after 6 months two shocks were blown and it was a rolly polly mess. The spring rates and soft dampers just killed it.
The spring rate (and damper) change was DRAMATIC - it always is. Even with much more mechanical grip from the 315mm tires the car cornered flatter and didn't do the extreme brake dive thing that stock S197s do. Again - don't throw your 4.6L GT away if you have one, they can still be fun. 
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