Header Selection Tip
What...
Header Selection Tip
What should you look for in a quality header? Because competition for your business is fierce in the header/exhaust industry, quality has never been better......
What about late-model Mustangs?
DL: Late-model Mustangs pose some concerns due to emission laws. In many cases, headers need to be compliant. JBA Headers was the original for catalyst-forward headers that met tough emission standards. The Cat4ward Shorty headers from JBA and Doug's Shortys will accommodate all original equipment emission controls while offering noticeable power increases. Most of these applications carry a California Air Resources Board E.O. number for legal use on street-driven cars. Additionally, JBA offers H and crossover exhaust systems that compliment the headers for better flow and a terrific musclecar sound. Long-tube headers designed for racing use, including engine swaps, are also available for late-model Mustangs.
.....Look for thick flanges,...
.....Look for thick flanges, solid welded seams for 360 degrees, and smoothly machined surfaces for a tight seal. The best header kits will include fasteners and gaskets. Another nice feature to look for is a tubular choke heat stove for automatic chokes.
We see all kinds of header sizes. How do you choose the right size and type?
DL: A change in tubing diameter and length alters the power band. This can get rather involved and there are many variables that determine optimum diameter. Rule of thumb is that you want to use the smallest diameter that will not hinder high rpm flow. Smaller diameter helps keep exhaust velocities high and that is where the largest improvements will be seen in terms of torque, which is what you want on the street. Bigger is not always better when it comes to headers, especially when low to mid-range torque is important.
Larger, more radical engines will require larger diameter primary tubes right off the ports. For most street-driven small-blocks in classic Mustangs, a 1 5/8-inch to 1 3/4-inch header tube is optimum while big-block and Cleveland cars can use anywhere from 1 3/4- to 2-inches. For the late-model crowd, shorty replacement styles will be 1 5/8-inch for both the 5.0L small-block and 4.6L SOHC/DOHC cars. Long tubes will run between 1 5/8- and 1 3/4-inches.
Few companies have been doing...
Few companies have been doing headers for classic Mustangs for as long as Hedman Hedders. Hedman has been around since the early 1950s and prides itself on producing some of the best headers in the industry. More than 50 different types of headers are available for '65-'10 Mustangs. This is the full-length Elite ceramic-coated header with 1 5/8-inch diameter primary tubes for '65-'73 Mustangs. They feature a fail-safe ball and socket collector to eliminate collector gasket concerns.
What about header coatings-painted versus ceramic?
DL: All three PerTronix Exhaust brands offer Metallic Ceramic Thermal Barrier Coating, which offers a couple of advantages over painted or raw steel headers. As the name suggests, this coating is a ceramic material that creates a thermal barrier. It holds more heat inside the header, which helps keep exhaust velocities high, which in turn improves performance. Additionally, it lowers underhood temperatures, creating a cooler intake charge to produce more power. As a side benefit, the coating increases corrosion resistance for longer header life while at the same time offering a much better looking and more durable finish than paint or raw metal. JBA headers are made of stainless steel, which naturally resists corrosion. The optional MCTBC coating on these headers does increase life while adding heat barrier advantages.
Common Header Installation Mistakes
1. Improper flange bolt torque-too loose or too tight
2. Primary tubes too large or too small
3. Collector size too large or too small
4. Header contact with body
5. Incorrect fasteners
6. Choosing long-tube headers that don't fit well with the underbody
7. Installing drag racing headers on a street car-typically too long and they hang too low
8. Headers that interfere with clutch equalizer shaft
9. Not installing a power steering ram header spacer/extension. Nearly all header manufacturers sell them.
The 2-inch header primary...
The 2-inch header primary tube size on this 289 is too large for a stock engine. This engine needs 1 5/8-inch or smaller for improved back-pressure and exhaust scavenging. It's always a delicate balance to get tube size so it's not too small (too much back pressure) or too large (not enough). When there's too much back-pressure, an engine suffers from exhaust restriction and power loss at high rpm along with excessive heat. When header tubes are too large, you lose back pressure and torque.
Ford Powertrain Applications...
Ford Powertrain Applications is all about Ford headers and exhaust systems......
.....Here's the FPA Jet Hot...
.....Here's the FPA Jet Hot ceramic-coated Tri-Y header on a 390 FE big-block. Note how close these headers tuck in to the engine.
The FPA Tri-Y header is so...
The FPA Tri-Y header is so compact you can nearly install a 390/428 FE big-block into a Mustang with them installed. In fact, you can install one side before the engine goes in. With both sides installed, they touch the shock tower just enough to create clearance issues.
Header fastener technology...
Header fastener technology has improved through the years. Stage 8 locking header fasteners (left) are the best out there and worth every dime. Get these bolts torqued to specifications and install the locks. They will never come loose. On the right is the more conventional header bolt with lock washer. This is what most header manufacturers provide with their header kits. They work fine, but the Stage 8 is better.
If headers aren't what you're...
If headers aren't what you're looking for, yet you want better performance, investigate the use of factory high-performance exhaust manifolds such as these 289 Hi-Po castings from National Parts Depot. They flow better than the standard 289/302 manifolds.
Header installation Tip
When...
Header installation Tip
When you're installing headers, make things easier for yourself by loosely installing the end header bolts first, then drop the gasket on the end bolts. The bolts act as a guide, keeping the gasket aligned. For proper sealing, evenly tighten the header bolts, then torque to manufacturer's specifications. And remember, use only the best gaskets, not cheesy paper types.
Position the gasket properly...
Position the gasket properly as shown. Watch the gasket closely when it's time for header installation. Position the header and start all bolts. Wiggle the header and check for gasket alignment. Use anti-seize compound on bolt threads.