Evan J. Smith
Mustang360 Network Content Director
May 8, 2014
Photos By: Kristian Grimsland

When it comes to classic hot-rodding tricks, one of the very first things enthusiasts do is modify the exhaust for better sound and performance. The tradition started long ago, in an effort to improve poor-flowing factory exhausts. Those stock pipes often consisted of cast-iron log-style exhaust manifolds and small (often single) pipes with many bends, rather than a straight dual-exhaust.

Thankfully, today's factory systems are better, but there is still room for improvement, especially when you crank up the power. The solution is to install aftermarket tubular headers, larger exhaust pipes, and free-flowing mufflers to create a better sound and increase power with a simple and often affordable bolt-on. In most cases you can install a new exhaust in your driveway or garage using basic handtools.

As you well know, there are lots of different headers on the market. There is also a swing in price depending on the materials, fit, and finish.

You'll find long-tube and shorty headers are both common mods for late-model Mustangs, especially in the Fox arena. The benefit of shorties is relative ease of installation. In most cases, they will connect to your existing mid-pipe and you'll see a gain in power. Long-tube headers will require a new (shorter) mid-pipe, but a properly designed set will often improve power.

Whenever selecting headers, it's most important to select a tube diameter designed to meet the demands of the displacement, cylinder heads, rpm range, and camshaft. The pipe length (of the headers), type of collectors, and remaining exhaust system can then be selected to offer proper scavenging to produce efficient exhaust flow.

We contacted BBK Performance to do a comparison on our '92 5.0 LX. Our trusty 5.0 was already wearing BBK 15⁄8-inch shorty headers (PN 1516), so all we needed were baseline horsepower and torque numbers on our Dynojet, then we could install the new pipes and test again.

The right pipes can make your Ford sing. This Magnaflow setup from BBK added over 10 peak rwhp and 17 lb-ft of torque at the peak over the old system. Under the peak we saw even larger gains.

We backed the headers up with BBK's catless X (PN 1660) and a Magnaflow aftercat that we scored from Brother's Performance Warehouse (PN MAG-15630).

“The BBK full-length headers are CAD-designed and manufactured with 15⁄8-inch, CNC mandrel-bent tubing; a 3-inch collector with a leak-free ball-and-socket-style (dome) collector for unrestricted airflow; and a one-piece, 3⁄8-inch, laser-cut exhaust flange for added strength and durability. All BBK headers are pressure-tested to ensure trouble-free performance,” said Tim Gilpin of BBK. “They are available in our standard chrome finish with optional high-temp, silver-polished ceramic coating. And all BBK header kits include new gaskets and hardware.”

Of course, every engine is different, but in this case, the long-tube headers outperformed the shorties. At the peak, horsepower jumped from 313 to 324 (an 11hp increase) and torque climbed from 329 to 346 (17 lb-ft), however, at 3,600 rpm, torque was up about 30 lb-ft, and just past the power peak (5,700 rpm), horsepower was up 15 hp. In fact, horsepower and torque were up across the entire curve.

With our little pony making 324 at the wheels, we're thinking about going with an electric fan next, and a few other tricks to see how much more we can squeeze from the budget 306.

01. The system on our LX consisted of BBK 15/8-inch shorty headers with a BBK X-style mid-pipe and Magnaflow exhaust.

02. Shop Manager Darrell Kunda removed the old exhaust by way of a sawzall and some power tools.

03. Next came the BBK shorties (PN 15150), which served us well.

04. The old system did well, producing 313 hp and 329 lb-ft of torque, but we wanted to see if long-tube headers would increase power.

05. The new BBK headers also utilized 15/8-inch pipes with an X-style mid-pipe.

06. To seal the headers to heads, we used Mr. Gasket gaskets and new locking header bolts, also from Mr. Gasket. One benefit of the bolts is the Allen-head center that allows you to run the bolts in, and even tighten them in tight places.

07. Kunda then slipped the new headers into place.

08. Then, the X-pipe went in…

09. … followed by the secondary mid-pipes that connect to the mufflers.

10. We went with a Magnaflowafter-cat that we got from Brother’s Performance Warehouse.

11. Lastly, the tailpipes were installed and aligned.

12. The BBK/Magnaflow system looks and sounds good. It offers an aggressive note, but is not too loud.

13. In the end, our 306 produced 324 rwhp and 346 lb-ft of torque. The engine has amazing tip-in throttle response and great mid-range power, which makes it loads of fun.