Reaching new heights with Heidts Pro-G Wide-Track front and rear IRS suspension system for 1965-1970 Mustangs

Mustangs capture the American spirit. They’re iconic with a storied history on the street, strip, and in open-track competition. With that, there are many ways to enjoy your Mustang, from racing to showing to just plain old cruising. But if you own a classic and are looking for enough punch to battle with the latest computer-controlled iron, you’ll need a dose of hp and modern suspension technology.lured in for a closer look, the deal was immediately sealed, ’cause beneath the open hood of this upgraded utilitarian was what appeared to have been transplanted straight from a ’67 Sting Ray-a 435hp Tri-Power 427. Or so we thought….

Giving This ’67 Mustang a Performance Makeover

The stock suspension is nice for a jaunt around town, but for spirited driving, the 50-year-old suspension won’t cut it. Adding power and modernizing your suspension is the ultimate solution, and our performance prescription came from the team at Heidts Hot Rod & Muscle Car Parts in Lake Zurich, Illinois. Heidts is well known for its killer suspension systems, and we had the chance to follow the build and drive its own 1967 Shelby tribute Mustang. Last month in the February 2017 Mustang Monthly, we showed what goes into installing Heidts’ Pro-G bolt-in independent rear suspension (IRS), as well as details of its all-new front suspension for early Mustangs. This month, we take that same car to the track to test how it all works.



Heidts specializes in adapting modern suspensions to all types of muscle cars and hot-rods. For this project, they went full boogie by installing a 5.0L Coyote, six-speed Tremec, Wilwood brakes, and brand-new front and rear suspension components in the classic Mustang. Heidts’ selected its Pro-G front and rear suspension, which incorporates a new front clip with upper and lower A-arms, coilover shocks, anti-roll bar, and rack-and-pinion steering. Out back, the Pro-G includes a wonderful IRS that’s designed with its own tubular cradle, 9-inch center section, coilovers, and inboard brakes. These professionally engineered systems infuse today’s technology with classic muscle to dramatically improve ride quality, braking, handling performance, and your fun factor.


As we showed you last time, BlackDog Speedshop in Lincolnshire, Illinois, did the heavy lifting, removing the engine, driveline, and suspension. The crew also prepped the underside of the unibody for its Lizard Skin ceramic undercoat insulation and sound-control formula by Mascort Corporation of Houston, Texas. “We used a blue tint to color match the body,” Heidts’ Wallace Leyshon said. “That provided sound control and thermal protection, as well as great aesthetics.”

The ride quality of this ’60s muscle car was improved dramatically and the handling characteristics are on par with 5th Gen and other high-end performance cars,” Leyshon says about the Pro-G suspension. “That was our objective for the Project Shelby.”

With the body ready to go, BlackDog installed the complete Heidts front and rear suspension systems and the 5.0 Coyote engine, the complete custom exhaust, fuel system, cooling, and master cylinder, plus they custom-bent most of the lines and hoses. Bruce Couture of Modern Driveline assisted, fitting the Tremec six-speed and Quartermaster driveshaft in place. BlackDog mounted the Ford Controls Pack computer through the firewall, which added protection and a factory-like look. It set up the parameters of the ECU, and the Coyote was barking. “We cannot thank BlackDog enough for going above and beyond, ensuring a clean install and ultimate performance,” Leyshon says.

The Hurst handle is connected to a smooth-shifting Tremec six-speed. 

A factory steering wheel hides the Dakota Digital speedo and tachometer.
The ride quality of this ’60s muscle car was improved dramatically and the handling characteristics are on par with 5th Gen and other high-end performance cars,” Leyshon says about the Pro-G suspension. “That was our objective for the Project Shelby.”
The heart of this Mustang can be found underneath, with the Heidts Pro-G front and rear suspensions. Up front, the IFS incorporates improved geometry and adjustability for all types of driving. The Heidts IRS is a work of art, providing show-quality looks with race-car performance. And when combined with the IFS, it can bring any 1964 1/2-1970 Mustang into the 21st century.

Fit and finish of the kit is simply amazing. The combination of the suspension and the American Racing VN 257 wheels (17×8, front and 17×9.5 rear with 4 1/4-inch backspace), wrapped in Nitto (P225/45ZR17 front and P275/40R17 rear) tires gave the Mustang a perfect stance. The Mustang now sits low and flat, but the question remained: Would it remain as flat and composed when pushed on track?

To find out, we put the Heidts Mustang to the test at Autobahn Country Club in Joliet, Illinois, sharing seat time with autocross specialist Danny Popp and Pirelli World Challenge veteran (and BlackDog Speedshop owner) Tony Gaples. “The Mustang was just terrific,” Popp says. “Its handling through the autocross turns was flat, and I could throw it where I needed to.”

Wilwood 6-six-piston calipers provide more than enough braking power for the Mustang. They are nicely modulated and look very racy.


Having driven the Project Shelby at Autobahn in its “before” condition, I was excited to see how much better it handled with the Heidts Pro-G suspension. I hopped in, clicked my belt, and cut loose. The 5.0L Coyote has endless revs and amazing power, and about 100 more hp than the pushrod V-8 that it replaced. But right away, I noticed how nimble and light the car felt.

The steering was precise and weighted nicely, which was a huge improvement over the stock power steering. I remember the factory steering being overly light and somewhat numb. Turn-in on the autocross was quick, but not to the point where the front end was nervous, and the Mustang exhibited a touch of body roll as it rotated around the cones. I enjoyed a high level of compliance with the tires, as they stayed flat to the pavement, even under hard cornering. This allowed me to cut in aggressively and put the power down hard and fast with no drama to speak of.

While I was hoping for a little oversteer to help it rotate on the tight autocross, the balance was more neutral, which is better for bigger tracks and sweeping corners. The team had the shocks in a stiffer setting, and even so, the ride quality was comfortable. A few clicks on the shocks would soften the ride for everyday driving.

Inboard rear brakes reduce weight at the wheel, which helps cornering performance and ride quality.

As a purist, I respected the factory, period look for the interior, including the seats, Hurst shifter handle, and steering wheel, which connected to the rack via a sweet ididit column. Even the Digital Dakota gauges had a stockish look to them. And while I rolled with the top down, if things heated up, I could have flipped on the Vintage Air A/C unit and cooled off.


The author of the Heidts’ Project Shelby sits at the wheel.

I had a blast ripping it up, and it was a sad moment when I had to hand the keys back to the Heidts team. Project Shelby matched the timeless looks of a classic Mustang with hp, handling, and braking that’s comparable to any new Shelby. Behind the wheel, you feel like the king—enthusiasts will appreciate the iconic looks, and on track, you’ll have the performance to show ’em who’s the boss.
Evan J. Smith

One Comment

  1. Project looks great!! Inspires me to plug ahead on my ’63 Falcon. Owned for 25 years, driven couple years, out of sight out of mind for nearly 20 years. Then few years ago a couple of “car” buddies convinced me to dig it out and get going. We started by cutting out the back half building new fender wells, trunk and new frame rails. Narrowed a 9″ rear end with posi. Put in a 1980’s 5.0 which somehow ? Blew up!! Currently have a 347 built and waiting for a front end. Retired and living on S.S. It takes awhile to save up for major components. Will keep ya posted.

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