James Lawrence
March 1, 2000
Contributers: James Lawrence

Step By Step

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It’s hard to believe that you can stuff four 2-inch tubes into such a little space.
This is the cut-up 5.0 that Pro Mustang uses to build and R&D new headers. As you can see, it’s been chopped fore and aft to ease construction.
Tubing of every shape and diameter is available so that Pro Mustang can build headers that fit the available space under your ’Stang.
The first step in building a set of custom headers is building a thick one-piece flange for them. Pro Mustang uses a tracer machine which is attached to a welder. The tracer follows the outline of this blueprint, while the welder cuts the flange from thick metal stock.
Some types of cylinder heads require port-plates in order to use larger primary tubes. These are included, if necessary, with the Pro Mustang headers.
Once the flange has been constructed, it is placed in a custom-built jig which allows construction of the header tubes.
Here are the tubes actually in the process of being formed. Each tube is composed of as many as three or four different welded sections.
The collector begins life as these five pieces.
Four pipe sections, of a smaller diameter than the header primary, are welded together. The welding process goes fairly quickly—heliarc welding isn’t required in this area.
Here are the four tubes after welding.
The four-into-one collector is then welded to the four smaller tubes. This is heliarc’d for a stronger bond and smaller weld size.
The completed collector (in our case a 4-inch) is bolted to the header tubes. It can easily be removed, which makes installation a breeze.
The cut-up car also saves the hassle of working on your back to fabricate the headers. You can see here the plate used by CHP to duplicate the JW bellhousing’s dimensions.
Here is our completed Pro Mustang 2-inch race header. We were impressed with their high quality.

These days, it seems that building a 9-second 5.0 is about as easy as a trip to the supermarket. Walking down the aisles, you pick up an assembled 347ci short-block; drop a set of CNC-ported heads in your basket; go to the deli and order up a dish of Vortech T-Trim, with cog-belts and 4-inch inlet tubes on the side. But when you get to point on the shopping list where it reads "race headers," the shelves are empty. You either have to make do with standard street/strip 1-3/4-inch full-length headers (and kill the top-end power of your new motor), or spend upward of $1,100 on full-custom build-'em-on-yourcar racing pipes. That is, until the smart minds at Pro Mustang Performance and Coast High Performance got on the job.

Coast High Performance sells a wide variety of Pro Mustang big-tube competition headers at a price racers can afford. Take a trip to just about any Fun Ford Weekend, the World Ford Challenge, or any other Pro 5.0 show--and you'll see what we mean. Big-name 5.0 racers--Mike Murillo, John Gullet, Jon Bennett, Joel Greathouse, and others--all rely on Pro Mustang headers for their 8-second power.

Last year, Coast High Performance purchased Pro Mustang from owner George Klass--including the rights to PMP's custom Big-Tube Headers, stroker swap kits, and intake manifolds. Since then, Klass, working for CHP, has significantly expanded the Pro Mustang "Big-Tube Header" product line to the point where now headers are available for more cylinder heads and in more sizes than ever.

Because we plan to make big power with the 10-Inch Terror's 351 stroker, nitrous'd powerplant, we knew we would need some extra-beefy header tubes to extract the big-time exhaust flow. Since off-the-shelf headers just won't do the job, we have two choices--the custom header route, which is expensive and time consuming, or a visit to the Coast High Performance/Pro Mustang headquarters to see if CHP offered a prebuilt race header that would work for our application.

It turns out that CHP's Pro Mustang headers are offered for just about every small-block Ford application. So, of course, CHP's technicians could build us the 2-inch primary/4-inch collector versions we needed for our Twisted Wedge-R heads. CHP can build headers for 302s and 351s with just about any commonly available head on the market (GT-40, Dart, Twisted Wedge-R, Yates, Edelbrock, Victor, Brodix, TFS Street heads, and more), but CHP also offers pipes for 460 and 351C applications.

Selecting the proper headers for your application is more involved than plunking down your credit card. According to Klass, the most critical factors in header design are primary tube diameter, collector size, and ease of installation. When it comes to headers, bigger is not always better, depending, of course, on your particular combination. Generally, any engine over 400 to 450hp (naturally aspirated, blown, or nitrous'd) can benefit from primaries at least 1-3/4-inches in diameter, in a long-tube design (short-tubes will cost you power at this level). The 10-Inch Terror, with well over 700 hp, needs the big 2-inch pipes. A stock short-block motor with heads, cam, intake, and a blower, making about 500 hp, can get away with a small 1-3/4-inch header, but there are advantages in going the more expensive custom-built route.

One big advantage is that the Pro Mustang headers can be built for any transmission type, including a T5, Tremec, C4, Powerglide, AOD, and Turbo 400. Try bending, denting, grinding, and banging your store-bought headers around that Powerglide bellhousing or Lakewood scatter shield. Pro Mustang headers are also heliarc welded, and built on a continuous one-piece flange to eliminate fitment problems.

Another great feature of all Pro Mustang headers is that they can be built with flanges using either a wider or staggered bolt-pattern, or a port-plate adapter.

Dart Windsor Sr. heads are notorious for having difficult spark-plug access due to relocated spark plugs. This access problem is a thing of the past with Pro Mustang's 1-3/4-inch Dart Windsor long-tubes using the Dart's wide-bolt-pattern header flange. Additionally, using the wider, staggered flange, or port-plates will allow room for a larger exhaust port.

Different primary tube diameters are offered depending on your expected horsepower, rpm band, and engine displacement. There are so many different combinations, that your best bet is to consult with the Coast High Performance tech staff to get the right header for your car. Pro Mustang offers their headers in 1-3/4, 1-7/8, 2, 2-1/8-inch sizes. Step headers, in which the diameter of the tubing increases from the head to the collector (often 1-7/8- to 2-inch), are offered for some applications. Collector size is another factor upon which the CHP staff should be consulted; however, 3-, 3.5-, and 4-inch collectors are offered for just about every header they make. The collectors are also of a "rotational firing order" design. The tubes are arranged so that the exhaust pulses enter the collector in a circular pattern, which CHP claims helps scavenging and can be worth 6 to 8 hp.

The best thing about Pro Mustang headers is that all of their offerings have been built and designed around a late-model Mustang shell with the proper engine size, trans, adapter plates, bellhousing, starter, etc. bolted into the proper locations. When you consider the different deck heights of the available Ford small- and big-blocks, the different transmissions, cylinder head types, bellhousings, starters, and engine locations, it can add up to literally hundreds of different combinations.

Take, for example, the 10-inch Terror's headers. We ordered them with 2-inch primary tubes, for a 9.5-inch deck-height 351, for Twisted Wedge-R heads, with a 4-inch collector, to be bolted to a Powerglide transmission. We forgot to tell CHP that we planned to run a JW SFI bellhousing for the Powerglide rather than an adapter flange! That was our mistake--especially considering that the #8 cylinder tube is different for that particular JW bellhousing (as compared to using an adapter plate for the Powerglide). When ordering these custom headers, the more information you give, the better.

We spent a day with the CHP guys to see the process of hand-building a set of high-quality race headers. The most noticeable thing in the header shop was a dismembered late-model Mustang in the middle of the floor. With the front end cut off in front of the shock towers, and the back half cut off at the quarter panels, it was the perfect model on which to build headers.

There are several steps to properly building a race header--cutting the flange, building the collector, and assembling and welding the header pipes in a jig. A pair of race headers takes about a full day for one Pro Mustang craftsman to complete, which tells you how much care is taken during their construction. Of course, that's not counting the R&D time needed to actually design each header for all those applications!

All in all, the Pro Mustang Big-Tube pipes are the only answer for the serious street/strip or race-oriented 5.0 Mustang. With such a wide selection of headers, for cylinder heads to different transmission types, you can rest assured that CHP can build a set for your ride. The cost for a set of race headers is between $550 and $695 depending on the diameter of the tubing and the complexity of the design, and they can usually be hand-built and shipped to your door within three to four weeks.