Hands On - Make Your Own Fender-Wall Headers

Ccrp 1204 Make Your Own Fender Wall Headers 000

There's no meaner look than a set of fender-wall headers hanging down behind your car's front tires. Sure, you'll need to slash away some factory tin to get clearance, but you'll also gain the benefits of simplified exhaust routing, the elimination of header-to-front suspension-interference hassles, and better engine breathing.

Ccrp 1204 Make Your Own Fender Wall Headers 001

You’ll need some basic welding skills and equipment to get this job done. If you don’t own a MIG welder, chop saw, and bench grinder, borrow or rent them from a friend.

You’ll need some basic welding skills and equipment to get this job done. If you don’t own

Watch as we cobble a set of mean tubes for this crazy Cammer-powered, altered-wheelbase, straight-axle '81 Fairmont sedan. We did it ourselves for about $350 in materials--a far cry from the $1,500 quote we got from an exhaust fabrication shop. Even if you think your ride doesn't need the in-your-face factor of fender walls, the techniques shown here can be adapted to the construction of conventional under car headers, too. Feed your head.

Limited-displacement engines like the 281-cube (4.6L) Cammer prefer smaller tubes to preserve torque. So we called Summit Racing and got fourteen 15⁄8 pre-formed J-bends (PN SUM621002, $14.95 each), a pair of 3-inch-diameter collectors (PN SUM14011, $48.69 pair), and 3-inch collector flanges (PN SUM15300, $7.69 ea.) that we’ll cap during street use.
Limited-displacement engines like the 281-cube (4.6L) Cammer prefer smaller tubes to prese
Summit doesn’t offer raw header flanges for the Ford DOHC mod engine, so we called JBA for a pair of laser-cut flanges (PN 46-158, $40.60 each). They’re made of beefy, 3⁄4-inch steel plate to resist warping.
Summit doesn’t offer raw header flanges for the Ford DOHC mod engine, so we called JBA for
The first step is positioning each collector where you want it to be. Make sure the temporary tack welds and metal tabs are strong and don’t move during construction.
The first step is positioning each collector where you want it to be. Make sure the tempor

The magic of J-bends is how you can cut them into many sections, then slice and rotate them to get the same effect as a tubing bender. In this shot, we used the chop saw to separate eight J-bends into three parts (marked 1, 2 and 3). Section number two will become the flange extension. It’ll feed into section number three.
The magic of J-bends is how you can cut them into many sections, then slice and rotate the
Regardless of engine type, you’ll need to form the round tubes to suit the header flange openings. The DOHC Ford mod motor employs unique ovoid exhaust ports leading from to its twin, 30mm exhaust valves.
Regardless of engine type, you’ll need to form the round tubes to suit the header flange o
A few light strikes are all it takes to flatten each round tube to fit into the flange. The modified tube is on the left.
A few light strikes are all it takes to flatten each round tube to fit into the flange. Th

Center each tube in the flange opening and weld two permanent beads. You don’t want the tubes shifting, rotating, or otherwise breaking loose during subsequent fabrication steps. This is no place for spot welds.
Center each tube in the flange opening and weld two permanent beads. You don’t want the tu
Here’s the semifinished flange. Note the wide gaps at the ends of each port. They’ll leak like crazy, but don’t worry—we close ’em up in a moment.
Here’s the semifinished flange. Note the wide gaps at the ends of each port. They’ll leak
Mask the exhaust ports to prevent grit and debris from poisoning the engine, then bolt the flanges to the heads so you can begin planning the routing of the primary tubes.
Mask the exhaust ports to prevent grit and debris from poisoning the engine, then bolt the

Remember pipe section number three that resulted when we sliced the first eight J-bends? With a small wedge sliced off each end (as shown), they mate perfectly to the extensions after being rotated 180 degrees. Work one cylinder at a time. The chop saw makes the cleanest cuts, though a hacksaw will suffice if you’re careful to work evenly.
Remember pipe section number three that resulted when we sliced the first eight J-bends? W
Three tubes are temporarily tack-welded to their feed pipes. Use a straightedge or piece of straight pipe to ensure they’re all level and evenly spaced. The leading pipe (on cylinder No. 1, right) is not shown, as it must be routed to clear the upper shock absorber mount. We’ll tackle it last. Ford mod motors place cylinders 5, 6, 7, and 8 on the driver side (from front to rear) and cylinders 1, 2, 3, and 4 on the passenger side (also front to rear).
Three tubes are temporarily tack-welded to their feed pipes. Use a straightedge or piece o
We’ll start running our tubes from cylinder No. 4. It’ll feed into the top-left opening of the collector. Note that we’ve removed some material from the pipe to yield proper alignment with the collector. Make sure your car’s front tires are in place and it’s sitting at normal ride height to prevent rubbing. You must ensure 1 inch of tire clearance with the front suspension at full compression.
We’ll start running our tubes from cylinder No. 4. It’ll feed into the top-left opening of

Position a J-bend against the existing tubes. Use an ink marker to indicate where cuts are needed. Measure twice . . . cut once. Here, the downtube has been tack-welded in place and the horizontal merge portion is being measured and marked for cutting.
Position a J-bend against the existing tubes. Use an ink marker to indicate where cuts are
One tube down, seven to go. As each primary tube enters the collector, remember not to apply anything more than small tack welds. The collectors will need to come off later so filler patches can be installed.
One tube down, seven to go. As each primary tube enters the collector, remember not to app
For cylinder No. 3, we started from the collector and worked up. Use your imagination to see what shapes you need to make based on the possibilities provided by the J-bends.
For cylinder No. 3, we started from the collector and worked up. Use your imagination to s

With the two outboard stations of the collector filled, we move inboard. The remaining primary tubes will need to run over or under the existing tubes. Here, we’re joining the bottom-right collector position to the No. 2 cylinder. A 70-degree transition was run from the collector upward. A 180-degree section of J-bend was then positioned loosely for marking and trimming.
With the two outboard stations of the collector filled, we move inboard. The remaining pri
The cylinder No. 3 primary tube has been completed in this shot. Note that the 70-degree transition from the horizontal collector to the upward trajectory of the primary tube was made by placing a wedge-shaped slice of tube at the union. Tack these joints so they stay together as you work.
The cylinder No. 3 primary tube has been completed in this shot. Note that the 70-degree t
The result of merging three pieces of pipe, this section is a perfect fit and will close the gap in the No. 2 primary tube.
The result of merging three pieces of pipe, this section is a perfect fit and will close t

Tack-welded into position, the No. 2 primary tube is done, and we can move on. Note the front wheels were steered through their entire arc during construction to avoid unwanted contact.
Tack-welded into position, the No. 2 primary tube is done, and we can move on. Note the fr
Here’s a view of the upper shock absorber mount. The No. 1 primary tube runs right into it, so we must go up and over (as shown). Again, the versatility of the J-bends simplifies the task.
Here’s a view of the upper shock absorber mount. The No. 1 primary tube runs right into it
Here, the No. 1 primary tube has been routed up over the shock mount, then rearward. It is merged into a section of the J-bend that’s been cut at the correct angle to allow it to target the final opening in the collector (top-right position).
Here, the No. 1 primary tube has been routed up over the shock mount, then rearward. It is

A simple span of straight pipe is trimmed to fill the gap and tack-welded in place.
Repeat the process on the driver side. Note that the stock Fox Mustang/Fairmont MacPherson strut front suspension has been replaced by a simple tube frame and straight axle to ease header packaging.
Repeat the process on the driver side. Note that the stock Fox Mustang/Fairmont MacPherson
It’s alive! With the snaky fender-wall headers and Sean Hyland eight-stack ram tube EFI setup, the Fairmont’s FRPP 4.6 Mach 1 Cammer crate engine (PN M6007M146) looks like a refugee from a vintage Funny Car . . . and that’s the point!
It’s alive! With the snaky fender-wall headers and Sean Hyland eight-stack ram tube EFI se

With the headers removed, finish welds are applied to each joint. Move the welder around a lot to minimize heat concentration, which can lead to flange distortion.
With the headers removed, finish welds are applied to each joint. Move the welder around a
We can now address the gaps in the port openings. A small pneumatic cutter slices the tube into sections for reworking.
We can now address the gaps in the port openings. A small pneumatic cutter slices the tube
Use a punch and hammer to make the tubing conform to the shape of the header flange. Try to create a gradual taper, as exhaust-gas velocity is highest in this spot. Abrupt obstructions kill power.
Use a punch and hammer to make the tubing conform to the shape of the header flange. Try t

Gaps are filled with weld and then smoothed with a grinder to ensure exhaust gases make an easy transition into each primary tube. A final bead of weld is applied to the outside of the flange to seal each primary tube and restore strength.
Gaps are filled with weld and then smoothed with a grinder to ensure exhaust gases make an
Remember we said not to finish weld the collectors until last? That’s so the space between the tubes can be plugged with a metal star (included with the collectors). Omit these plugs and massive exhaust leaks are guaranteed.
Remember we said not to finish weld the collectors until last? That’s so the space between
With the stars in place, the collectors can be finish-welded onto the ends of the tubes. We added 21⁄2-inch branches that’ll feed into the muffled system when we run on the street. Three-bolt collector flanges (PN SUM15300, $7.69 each, 3 inches; PN SUM15212, $6.39 each, 21⁄2 inches) receive collector caps and under-car head pipes, respectively. Note that the branch on the right has not been welded yet. Back in the ’60s, we’d have applied high-temperature header paint to prevent rust. Today, we’ll send ’em off to one of the big commercial coating houses for application of a ceramic thermal barrier, inside and out.
With the stars in place, the collectors can be finish-welded onto the ends of the tubes. W

SOURCES
Summit Racing PO Box 909 Akron OH 44398 800-320-3030 www.summitracing.com	JBA Headers 7149 Mission Gorge Rd. Ste. D San Diego CA 92120 800-830-3377 www.jbaheaders.com
Ford Racing Performance Parts 15021 Commerce Drive S Suite 200 Dearborn MI 48120 800-FOR-D788 www.fordracingparts.com	Sean Hyland Motorsports 691 Jack Ross Ave Woodstock 519-421-2291 www.seanhylandmotorsport.com