General Motors is no stranger to timeless designs — from the Tri-Five Chevys and the ’59 Eldorado to the ’63 split-window Corvette and the square-body pickups of the 1970s and 80s, GM has produced no shortage of automotive icons. But while the aesthetics can be difficult to improve upon, the march of time has ensured that the technologies these machines were originally equipped with certainly can be.
Our A-Body, Project Payback, serves as a prime example. Underpinning everything from the original Pontiac GTO to the first-generation Buick Regal, it was an incredibly popular platform back in the day, and one which can trace its development roots all the way back to the Eisenhower administration. Automotive engineering has changed quite a bit in the past 60 years, and that’s one of the reasons we looked to Schwartz Performance for a modern take on this classic chassis design.
Both our Schwartz Performance A-Body chassis and the pushrod 6.2-liter LT4 we've dropped into it could be considered contemporary interpretations of old school designs. But while both work off of well-established templates, the disparity in development age between a chassis design that has its roots in the early 60s and an engine that debuted in 2015 under the hood of the C7 Corvette Z06 is truly vast. And means that getting everything to play nice in terms of packaging and clearances can be tricky if you don't have components that are made specifically to support this combination.
We took a similar approach with its motivation, as well. Once considered the golden era of performance, even the most potent engines of the original muscle car era are wholly outgunned by the V8s that are readily available today in terms of power, efficiency, strength, and reliability. And that’s why we snagged an LT4 crate motor from Chevrolet Performance, an engine that in factory-stock and fully-warrantied form makes horsepower legends like the LS-6 and L88 look tame by comparison.
But while these modernized components ensure that enthusiasts can have their cake and eat it too, marrying a reworked chassis design with a modern powerplant also comes with some important considerations, particularly when it comes to packaging and overall fitment. Accordingly, we hit up the folks from Ultimate Headers to get a set of headers that employ a similar engineering theme while also being purpose-built for the application. Here we’ll take a closer look at how the Berea, Ohio exhaust manufacturer is bringing a new perspective to a long-stagnant segment, and get these new pipes hooked up to that supercharged mill.
Engineering Innovation
“We have a saying around here that it’s the first header redesign in 80 years,” says Ultimate Headers’ Jim Browning Jr. “If you put 10 different headers side by side, they all look basically the same. We wanted to take a fresh approach to a product segment that, quite frankly, hasn’t changed much in decades. So when you put ours next to that lineup, you’ll see dramatic differences.”
Ultimate Headers was established in 2012 by Corsa Performance founder Jim Browning Sr., who sought to take the modern perspective he brought to muffler design and engineering and apply it to headers. And by taking a holistic approach to the issue, Ultimate Headers has created products that differ from those of its competitors on a fundamental level.
“We wanted to have a product that was different from everything else that was out in the marketplace in terms of header design, materials, and that sort of thing. And because of that, we are the only manufacturer to build headers from 321 stainless steel on a production-type basis,” Browning notes.
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“We use a 3D modeling program called Solidworks for our development,” Browning says. “Compared to traditional R&D methods, it’s much less time-consuming and far more precise. You don’t have somebody spending 12 to 15 hours hand-building a header the old-fashioned way, taking miscellaneous mandrel-bent tubes, cutting them, and tacking them together piece by piece. If you design it off of the computer with engine and chassis data from the manufacturers right from the get-go, you’re able to create fixtures and everything around that component for production-intent purposes while skipping a lot of the guesswork along the way.”
“Versus the 304 stainless steel that’s traditionally used in header manufacturing, 321 stainless is 50-percent stronger at 900+ degrees Fahrenheit.” Regularly used by teams in Formula One, NASCAR, and pro-level endurance racing, this material has been proven to withstand the prolonged high-temperature stresses that are inherent to top-tier motorsport, and its bolstered resistance to thermal cracking also makes it a natural choice for boosted, high-horsepower builds.
The company took a fresh approach to its flange design, as well.
“If you look at headers from the day the first set was produced up to today, you’ll notice that everybody just uses a stamped or laser-cut 3/8-inch plate across the cylinder head, and it’s a design that looks like very little thought has been put into it,” Browning says. “But we have a tremendous amount of experience with investment casting and, after going through some finite element analysis and testing, we created a model of what we wanted. That means that our flange has the same clamping force and yet is stiffer than a typical 3/8-inch plate due to the ridges we’ve designed into it. There are also no exterior welds at the flange because ours are welded to the back and inside, so it’s a much cleaner-looking installation.”
Ultimate Headers’ casting is also flat, and its welds aren’t applied to the mating surface, which in turn results in a very leak-free mounting surface between the header and the cylinder head, Browning tells us. “And because of this unique design and the benefits it provides, we were issued a design patent on our flange. You won’t come across anything else like this in the United States.”
The most common method used to put a bend in a tube is to use a traditional tube-bender, but this approach comes with a notable compromise: the material on the outer portion of the tube is stretched to accommodate the bend, its wall thickness is reduced in those areas. Ultimate Headers takes an entirely different approach, combining mandrel-bent tubing with investment cast elbows to provide increased design freedom without compromising the integrity of the part.
“It allows us to produce a part that has a uniform wall thickness throughout the entire component,” says Browning. “That gives us the ability to use a much tighter radius than you can have through normal tube bending.”
Ultimate Headers’ tight-radius elbow is another key design element that sets its products apart from the pack, and it comes as a result of its unique manufacturing process.
“That allows us to design the headers so they’re close to the engine block and clear the steering components,” he points out. “Nobody else has ever used a cast elbow in the design and manufacturing of headers. Other manufacturers may trim a tube on a bend, and the tube isn’t exactly round in the way that it connects at the port, and that means it isn’t optimized for proper airflow out of the port of the cylinder head. With our design, we don’t have to compromise that airflow.”
"That heat can warp those plates," Browning says of traditional flange designs. "And that makes it difficult to have a flat surface that doesn't leak. But because of the way our castings are designed there's no heat at the port, so they stay flat and flush. You could almost run them without a gasket, they're that flat. And nothing is MIG welded - everything is hand TIG welded for a cleaner fit and finish." Ultimate Headers also incorporates their extreme low-profile clamps into most combinations, which provide up to 13 degrees of articulation. "That adjustability allows the builder to come off the header and tilt it in, out, down, or up, as needed and get the exhaust system started from the clamp when body or ground clearance is at a premium."
And all of Ultimate’s headers are built within a steel fixture, so quality is the same with every set.
“The fixturing is critical – we want to build the best header possible each and every time,” Browning notes. “If you don’t have a tight manufacturing tolerance, you may get a header that fits one car but not another, so there are points of interference that our headers have to fit within in order to meet our production standards.”
Nobody else has ever used a cast elbow in the design and manufacturing of headers. Other manufacturers may trim a tube on a bend, and the tube isn’t exactly round in the way that it connects at the port, and that means it isn’t optimized for proper airflow out of the port of the cylinder head. With our design, we don’t have to compromise that airflow.
A Purpose-Built Piece
Ultimate Headers also offers five different coating options to tailor each set of headers to thee intended application.
“The standard is our mill finish,” Browning explains. “And the other four options all have a mirror-polish flange. There’s a brushed stainless finish, a full mirror-polished finish that basically looks like a piece of jewelry, and we also offer ceramic coatings in silver or black. The ceramic coatings will give you a 150- to 200-degree temperature difference and help keep the heat in the header, rather than allowing it to radiate throughout the engine bay and potentially into the cab of the vehicle.”
Because Ultimate Headers has a specific part number for this combination (and the fact that there's no bodywork or other components to work around), ditching the factory stuff for these new long tubes was basically just a matter of unbolting the old manifold and hooking up on our new headers in their place. Browning says we should expect to see a 20 to 25 horsepower gain at the wheels from the swap on an otherwise stock LT4.
We opted for the latter on our build, and the header itself is designed specifically for this engine and chassis combination.
“The LT engines are becoming more and more popular for these swaps, and customers were demanding a part that made sense for these current-generation engines,” Browning says. “And that means the installation here is pretty straight-forward. On A-Bodies there’s a lower control arm mount that protrudes to the inside of the frame rails, and that header is designed specifically for that engine in that chassis, so it gets around that lower control arm without issue. We’ve taken the time to engineer specific part numbers for specific applications like these.”
"We have part numbers specific for Chevy IIs, Camaros, Corvettes, C10 trucks, G-Bodies - if you can dream it, we can build it," Browning says. "We are working on some headers for a '59 Cadillac right now. And the new LT2 could be available as a crate from General Motors within the next year or so, so that's definitely on our radar as well. Hot rodders are always looking outdo the next guy with the latest and greatest stuff available, so I don't think it'll be long before we see this new engine finding its way into builds."
And the same holds true for the other GM platforms that Ultimate Headers support, as well. “There’s no such thing as one-size-fits-all,” he adds. “For instance, the steering box in a stock Tri-Five Chevy is in the way, and that is an extremely tight application. So that header is designed uniquely to pair an LT4 to that vehicle, and it’s a different part number if it’s a production chassis or a Schwartz Performance chassis, or an Art Morrison chassis. It’s expensive to take this approach, but our clients expect something that’s designed to drop right in. It’s essentially a semi-custom-built item that’s also readily available. We want to make it easier for people to build their dream cars with a very high-quality product that you can’t get from anywhere else in the world.”