Back in the early days of hot rodding, necessity was the mother of invention, as crafty gearheads would fabricate their own speed parts due to a lack of aftermarket support. Now, we have a tremendous offering of components at our fingertips, but even then, the aftermarket doesn’t support every build and every application. When this is the case, custom fabrication steps back into the fold, allowing for handcrafted fitment and custom design. While some fabrication projects can be tackled by a beginner, others get a little more complicated. We’d classify custom long-tube stainless steel headers as a pro-level task, but with the proper tools, skills, and patience, it can be done.
The raw materials needed for a custom header build include 1-7/8-inch 180-degree mandrel bends, which feature a 2- and 3-inch center line radius, giving Old Anvil’s Nick Andreos and Brandon Gerringer plenty of options for bends. All materials are 304 stainless steel.
We recently had the opportunity to follow along as Old Anvil Speed Shop in Orange, California, built a set of headers for a wild ’67 Nova, which has an LS engine topped with a tunnel ram and two four-barrel carburetors. This old-school combination is bolted to an aftermarket subframe, but it’s still a tight fit in the small Nova engine bay. Nick Andreos and Brandon Gerringer at Old Anvil Speed Shop handled the fabrication job, starting with 304 stainless steel 180-degree mandrel bends. There are a few options for header flanges, but the custom look of the cast stainless steel flanges is hard to beat.
Andreos started by bolting the Ultimate Headers flanges to the cylinder heads, using ARP hardware. These two-piece flanges are made from cast stainless steel and feature a super-cool look.
There are many specialized tools that aid in the fabrication process, and you’ll see them at work in this article. Mock-up tools are a lifesaver for header fabrication, as is a lift to access the top side and bottom side effortlessly. As with any fabrication project, there is a lot of mocking up, test-fitting and tweaking, so having easy access to all angles is essential. Stainless steel can be tricky to work with, as it doesn’t cut or weld as easily as mild steel, but the results are far superior when it comes to the appearance and longevity of the headers.
Icengineworks makes a series of header fabrication tools, which are used to create the mock-up for the bends. The pieces lock together, allowing Andreos to assemble the primary tubes.
The guys at Old Anvil Speed Shop spent approximately one week building these headers, so they certainly come in at a higher price than your average off-the-shelf headers. In the case of this wild ’67 Nova, the custom touch and excellent fitment is worth every penny.
Andreos uses a band saw to cut one of the 180-degree bends and then uses his mock-up to determine the proper cut to fine-tune the fitment.
Follow along as a pile of tubing gets sliced, diced, and welded into a custom set of stainless steel headers that takes this Nova to the next level.
The goal of custom headers is having a nice, tight bend that looks good, but still allows proper clearance on the steering, spark plugs, and other common interference areas.After the primary tube is mocked up, test-fitted, and prepared for welding, Andreos tack-welds it to the header flange while it is still bolted to the cylinder head.Welding stainless steel requires attention to detail, and Andreos sands, files and cleans the end of each tube before it is welded. Inconsistencies in the surface and burrs on the inner diameter can cause poor welds.The Icengineworks mock-up system is once again used on the bottom side, as the primary tubes converge into a collector. Old Anvil Speed Shop uses a collector template to bring the four tubes together in a precise manner.Moving onto the passenger side, Andreos must route the primary tubes around the starter. This can get extremely tight, especially on the early Nova platform.Some primary tubes can be fabricated using long pieces of tubing, while others require smaller sections, which will be stitched together to create the necessary bends.Underneath, the primary tube for the number six cylinder is being pieced together using three pieces of tubing. Notice the marker designations, which help Andreos find the proper orientation if he removes a piece for fine-tuning.Once fitment is complete, Andreos takes great care to sand, deburr, and clean each tube. Here, he uses a red scuff pad to smooth the inner diameter of a primary tube after filing off the burrs.Now it’s time to remove the header flanges. This allows Andreos to finish-weld each section and then assemble the lower section, which is mostly made up of straight tubing.An important part of fabricating stainless steel headers is purging the welds. The hose running into the tube emits Argon welding gas from a second tank to protect both sides of the weld. Andreos seals the hose with tape.On the flange side, Andreos uses steel wool to create a restriction, but he does not completely seal it off. He wants a small amount of flow to allow the ambient air to escape. This extra step reduces corrosion and makes for long-lasting welds.Andreos TIG welds the header tubes with great precision and then cleans the areas with a wire brush for a clean look.Andreos has tack-welded the top side of the primary tubes to the flanges and the headers are starting to take shape. Once he is happy with the fitment, he lifts the car and begins building the collectors.Underneath, he uses collector templates to help align the four primary tubes. The seemingly simple process of attaching straight tubes to the bottom side still requires a special level of detail.The collector template bolts to the car, to provide a consistent distance between the headers and floorpans. With the tubes welded, it’s time to trim the excess material and weld on the collector.These merge bullets come in four pieces and are tack-welded and fitted to the end of the tubes. Once the fitment is verified, Andreos welds the seams and grinds it to a slick finish.After the bullets are welded and smoothed, Andreos welds them to the header collectors. This cone helps send the exhaust gases out of the tubes efficiently.Onto the collectors, Andreos uses a combination of a pre-fabbed collector and a reducer, which is used to connect the collector to the V-band flange.The finished collector is ready to slide onto the header tubes, but not before Andreos repeats this process for the other side.Before the collector is installed, Andreos bolts the V-band flange and the beginnings of his exhaust system to the collector. From there, he can weld the flange onto the exhaust pipe.Back to the welding table, Andreos bolts the headers to an old set of cylinder heads to complete the final welding. Again, he purges the welds, but uses a different technique this time.Andreos manually opens an exhaust valve and inserts a small piece of wire, once again allowing a small amount of ambient air to escape the tube. Meanwhile, Argon gas is flowing into the tube from the other side.After the collectors are welded in place, it’s time for a final install, where Andreos can turn those ARP bolts for a final time and install the exhaust system using V-band clamps.While off-the-shelf long-tube headers can cost anywhere from $150 to $2,000, a custom set of headers will set you back quite a bit more, depending on the complexity and materials used.In the case of this LS-powered ’67 Nova, Old Anvil Speed Shop spent approximately one week building these custom stainless steel headers. The final result is excellent fitment, and one-of-a-kind cool factor.
Sources
Automotive Racing Products (ARP)
(800) 826-3045 arp-bolts.com
