SEMA 2018: Roadster Shop SPEC Chassis For Classic Mustang

The Roadster Shop has become synonymous with restomods. Making an old car handle better than a modern one is its specialty. Even though the name suggests street rods, Roadster Shop (RS) is about much more than roadsters; it doesn’t specialize in any specific style of car and is equipped to tackle all aspects of vehicle builds. It is known for its chassis and suspension setups, but they build anything from a period-correct restoration to a full-on custom, one-off, turn-key street machine.

Many high-end builders used Roadster Shop chassis under their cars to bring performance up to modern standards. This was one of the latest from Kindig It Design.

For more than 25 years, Roadster Shop has been designing, engineering, and innovating the development of chassis and suspension products to the growing Pro Touring market. Previously known for its Fast Track and Revo chassis lines, a couple of years ago it introduced a new line of chassis which introduced its award-winning chassis to a whole new demographic. The SPEC Series chassis offer the same outstanding quality at a more attainable price point for the Average Joe over the other two lines. Using what it learned from building the other two chassis styles through the years, RS found ways to streamline its procedures on some of its popular chassis setups to lower the costs and reduce lead times.

Instead of having to try to modify a weak 60-year-old frame, the SPEC Series chassis have made it possible for an enthusiast to start with a light, strong, complete chassis and just drop on the original body. The latest offering is sure to be a hit. Early Mustangs aren’t exactly the worst suspension setup in the world, but they could certainly stand some help, so the minds at RS developed a SPEC chassis for the 1964 to 1970 Mustang.

This is George Poteet’s latest acquisition. It was built in-house at the Roadster Shop, and was one of the first to receive the new Mustang SPEC Series chassis.

Using high-resolution 3D scanning technology, Roadster Shop mapped out a model of the original Mustang floor pan and undercarriage to design an entirely new chassis system that contours to the original pan. Using its exclusive “Laser Rails” and CAD design allowed RS to develop a Mustang-specific version of the SPEC IFS (independent front suspension) that works with the narrower track width of the early Mustangs. The new crossmember was engineered to allow for off-the-shelf wheel fitments and accepts a wide variety of engine packages including SBF, Coyote, and even LS.

Speaking of engine options: purists are going to hate it, but in one of the most cleverly disguised swaps we've ever seen, this is actually an LS engine. The RS guys even had a little fun at the expense of those who might be offended — it's all in good fun.

It is a true industry-first full chassis system for the ‘Stang. The front track width is 59-inches with spindles and brake packages that accept wheels as small as 15-inches in diameter. The rear track width is 59.5-inches and allows the same wheel options as the front to fit within the wheel tubs for a square and rotatable wheel setup. If you want a wider wheel out back, no problem. The rear framerails mount to the factory leaf spring hangar locations that are set inboard of the factory sub-rails allowing for a 12-inch wide wheel with a 345 tire when mini-tubbed. Narrowed rearends are also available.

The driveline is positioned so that a Tremec T56, TKO 500/600, and 4L60 transmission will clear the factory tunnel and the shifter aligns with the original opening — no cutting necessary! Additionally, the stance will benefit from the low-profile design of the chassis, which sits only 3/8-inch lower than the factory sub-rails. The RS SPEC IFS suspension geometry features a double wishbone, eliminating the antiquated strut-based system.

Looking inside you'd have no idea this Bullitt Mustang has modern underpinnings. The good part is the floor and tunnel don't have to be modified to accommodate the 4L60E transmission lurking below.

Additionally, the gas tank mounting remains unchanged, so any OEM, OEM replacement, or drop-in aftermarket tank can be used. The front core support is also left unmodified, so any replacement or aftermarket radiator can be installed without worry.

This chassis is a true bolt-in solution. There is minimal work that has to be done to accommodate this new chassis. The channeled front framerail and bolt-on upper suspension mounts are engineered to fit to the existing factory sub-rails and inner structure once the seams are removed and a few holes drilled. The rest of the chassis bolts right up to the six existing factory body-mount locations.

The new SPEC chassis bolts right in place and allows the use of the original gas tank location and wider wheels if so desired. There aren’t too many people who can use that license plate surround!  To see the entire gallery of the build as it progressed, go HERE.

Here are some of the build shots from Roadster Shop's website. You can really see how well the chassis mates with the original body. Having modern suspension underneath, we're sure George is really going to enjoy the ride.

Putting together a frame and suspension setup with the original parts will cost you as much as it would to buy a new Roadster Shop SPEC Series chassis and it won’t handle near as well. It becomes a no-brainer when you look at all the time involved in sourcing the parts, researching the geometry and setup, and just doing all the necessary work to get it all lined up. With the new SPEC chassis from RS, you’ve got it all ready to go for you, and you know the quality will be top-notch. If you’re restoring/restomdding an old Mustang, check out the Roadster Shop website or give them a call.

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About the author

Shawn Brereton

Shawn is a lifelong car enthusiast who appreciates all things automotive. He is the proud owner of a blown '55 Chevy, a daily-driven '66 Fairlane with an '09 GT500 drivetrain, and a '96 Miata track car.
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