How Modern Chassis Design Breathes New Life Into Vintage Performance

While getting your hands on a modern performance car that will pull more than one lateral G on the skid pad, or effortlessly cruise for hours on end, is simply a matter of trotting on down to your local dealership, there’s a look and feel to old-school machinery that late-model automobiles simply can’t deliver.

It’s one of the many reasons that builders continue to turn to vintage hardware for their performance projects. But, getting a 50-year-old vehicle to dance around a road course or grand tour like the latest offerings from mainstream automakers isn’t simply a matter of bolting on a set of coilovers and some grippy tires.

The era before government-regulated automotive design gave us some undoubtedly stunning machines, and they’re vehicles that are obviously well worth keeping on the road. However, just because you restore an automobile in 2018 does not mean it will ride and drive like one designed in the 21st century.

Half a century of engineering advancement can have a profound impact on design in any field, and the automotive realm is certainly no exception to the rule. It’s for that reason that a growing number of companies offer chassis and suspension components that allow enthusiasts to retrofit contemporary technology into their vintage rides in a way that modernizes these vehicles on a fundamental level, as opposed to simply bolting upgraded components onto a dated and potentially compromised factory platform.

To get a better sense of exactly what that entails and how it affects the capability of vintage performance cars, we got the low-down from the experts at Art Morrison Enterprises and Chris Alston’s Chassisworks about what they offer and how they merge old-school cool with new-school tech in a way that benefits both sides of the equation.

Technological Advancement

Serving as the “bones” of the vehicle, the chassis and frame play a central role in dictating how that automobile will perform. While the desire to maintain originality is alluring for many, the benefits of a modern chassis are vast. In some situations, it also allows builders to put cars back on the road that might otherwise be too far gone. “There’s a couple of different factors at play here – one of them being that these older cars from the ’40s, ’50s, and ’60s have seen a lot of weather and a lot of road miles over the years, more often than not,” says Craig Morrison of Art Morrison Enterprises.

Modern chassis design allows builders to give vintage performance cars a level of chassis rigidity, suspension sophistication, steering response, braking capability, and tire compatibility that racers only could have dreamed of back in the 1960s.

“So many of these original chassis aren’t really in good enough condition to be worthwhile to try to salvage, and we have the opportunity to vastly improve upon the original design. What we do is design a brand new platform that is much more rigid than the original chassis and utilize modern-day types of suspension, which in turn provides ride and handling qualities that most people are expecting when they build a hot rod or muscle car.”

That last bit Craig mentions is something that’s easy to overlook when diving into a vintage performance project, and it’s important to remember that a “brand new,” factory-stock, 50-year-old car still functions like a 50-year-old car would. “The main benefit of doing modern chassis upgrades is that you can improve the suspension geometry while also removing the free play in the chassis and suspension,” says Lino Chestang of Chris Alston’s Chassisworks. “That translates to more precise control over the vehicle and more immediate response overall.”

Chris Alston's Chassisworks' gStreet Camaro system modernizes the vehicle from the ground up, starting with a full box tube frame and prefabricated floors that allow builders to install up to 345mm tread out back, along with a range of different adjustable front- and rear-suspension setups, rack-and-pinion steering, big-brake kits, and modern powertrains, if they so choose.

Compared side-by-side, the improvements offered by modern chassis components are obvious. “A lot of these vehicles originally just used a stamped-steel-chassis design that had sort of rudimentary open-channel cross members, either riveted or spot-welded at the front and rear,” Morrison explains. “There was very little between the front and rear suspension to make that frame rigid. It sort of relied on the body itself to provide any sort of rigidity, and the chassis was really just there to mount the engine and suspension points.”

A lot of these vehicles originally just used a stamped-steel-chassis design that had rudimentary open-channel cross members, either riveted or spot-welded at the front and rear. There was very little between the front and rear suspension to make that frame rigid. It sort of relied on the body itself to provide any sort of rigidity, and the chassis was really just there to mount the engine and suspension points. — Art Morrison

Design, Engineering & Manufacturing

Along with the technology gap between vintage components and modern-day hardware, it’s also important to recognize the compromises inherent in mass-produced vehicles. Cost is a primary factor for OEMs, and it affects a vehicle’s design, both in terms of cost of its hardware as well as the complexity involved in manufacturing that vehicle. The upshot is that the components offered by companies like Art Morrison and Chris Alston’s Chassisworks really could not have been offered by OEMs back in the day, even if they’d had the means to do so.

“The frames that we build are primarily 2-inch by 4-inch rectangular box tubing that we then mandrel bend in-house,” Morrison tells us. “With our heavier and longer wheelbase cars like Cadillacs and some of the hard top cars of the ’50s and ’60s, we’ll actually use 4-inch by 4-inch box tubing that’s even more rigid, with either .120-inch or .180-inch wall thickness. The weight of the vehicle and how it’s going to be driven both factor into that design process.”

Morrison points out that even basic modern economy cars are light-years ahead of the most capable machines that came out of Detroit back in the day, and that can catch some folks off-guard. “Whether customers who are building cars now realize it or not, they often have a really high expectation of how a car should handle and perform,” he adds.

Factory-produced vehicles are designed and manufactured to a specific cost to the OEM, and 50 years ago, that translated to some significant compromises. Modern chassis components can address many of those potential issues while maintaining the car's original style.

“The manufacturing tolerances on those cars were very loose, to say the least,” Chestang says. “You can actually take, say, three different ’65 Mustangs, check the measurements, and come back with three totally different sets of numbers. Modern manufacturing gives you incredible control over the accuracy of the manufacturing process, and that alone makes a big difference behind the wheel.”

Benefits On The Street And At The Track

Though there’s an array of advantages to retrofitting vintage vehicles with modern chassis hardware, perhaps the most obvious is the ability to bolt on components that otherwise wouldn’t be compatible with the vehicle, like modern brakes and high-performance wheels and tires. “When we first did our ‘55 Chevy, the group that tested it did a braking evaluation on a bone stock ’55 Chevy with bias-ply tires with the best brake shoes you could get for all four corners,” Morrison says. “60 miles per hour to zero took 311 feet. When was the last time you were on the freeway with a football field of clearance in front of you? It just doesn’t happen.” By comparison, a late-model Chrysler Pacifica minivan stops from the same speed in just 120 feet.

Though the benefits of these upgrades are perhaps most obvious in performance and motorsport context, they'll also provide a much more drivable and predictable vehicle for around-town cruising as well.

 

The manufacturing tolerances on those cars were very loose, to say the least. You can take three different ’65 Mustangs, check the measurements, and come back three totally different sets of numbers. Modern manufacturing gives you incredible control over the accuracy of the manufacturing process, and that alone makes a big difference behind the wheel. — Lino Chestang

“A lot of our approach is about replacing the suspension design in general, rather than just swapping components,” says Chestang. “We have a complete line of triangulated four-links, Watts-link, and torque-arm suspension systems that are direct fits for cars that were equipped with leaf springs from the factory. Leaf-spring systems were made to be cheap, and they were given multiple tasks – controlling the torque reaction, the lateral location of the housing, etc. The suspensions that we use basically split up those functions so that we can build a specialized component to handle those tasks more effectively.”

That can translate to a vehicle that hooks up better at the drag strip, or corners with more tenacity on a road course, or simply cruises more comfortably and confidently around town and out on the highway, depending on what the customer wants from the build.

Here, a steering rack is tested for the correct amount of resistance, per customer specification, before being installed in the vehicle.

The benefits of added chassis rigidity are also substantial, as they improve the performance of all of the components that are bolted to it. “Flex in the chassis has the potential to take capability away from the suspension,” says Art Morrison’s Matt Jones. “If the chassis flexes enough, it can take the suspension geometry out of its specification during that moment, which can affect steering response, grip levels, and other handling characteristics.”

Jones points out that it’s not something that can be overcome by simply bolting on a stiffer set of springs and dampers. “What’s the point of spending a ton of money on shocks when the suspension’s not really going to be able to do its work? Say you’ve got a stock C2 Corvette roadster. All that flex is in the body — expensive dampers aren’t going to help that one bit. Until you take care of that flex, the suspension isn’t able to work as efficiently as it can.”

It’s a similar story with steering systems, too. “You could drive down the road in most vintage cars and move the steering wheel an inch or two off-center and not feel it,” Chestang points out. “They’re also typically pretty slow steering ratios. For instance, stock early Mustang racks require 4 and 5/8ths turns lock-to-lock. Our rack-and-pinion steering racks cut that down to about three turns lock-to-lock, and there’s no play in the wheel.”

Chestang explains that, like their other chassis upgrades on offer, they chose to address the design of the steering system rather than try to improve upon the factory setup. “We could have taken the minor upgrade approach and just upgraded the OEM rack,” he says. “Instead we went ahead and completely re-designed it. A lot of people have tried to put end take-off rack and pinions on these cars and run into problems with the original drag-link suspension design – you’ll never get the geometry right. Our center take-off rack lets us move the control servo and pinion right up against the driver’s side framerail, so you’ve got plenty of header clearance and the geometry is exactly what it’s supposed to be.”

But this is just the tip of the iceberg in terms of how the latest chassis components and designs can transform vintage automobiles into truly modern performers and highly-capable cruisers. Looking to elevate the ride and handling prowess of your old-school performance machine? The folks at Chris Alston’s Chassisworks and Art Morrison Enterprises have the hardware and expertise to help you get that setup dialed in right where you want it, whether your ambitions take you to the drag strip, road course, or your local cruise night.

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About the author

Bradley Iger

Lover of noisy cars, noisy music, and noisy bulldogs, Brad can often be found flogging something expensive along the twisting tarmac of the Angeles Forest.
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