Header Selection Tip
Header...
Header Selection Tip
Header selection isn't just about tube and collector size or even what type of coating you choose. It's also about ease of installation. How easy are they to install? Not all header flanges are easy to get a wrench on. Check fastener clearance with a simple closed end wrench. Closed ends will not always fit all bolts. Sometimes, you must use a box-end wrench. Wrench fit is the measure of a good header. Manufacturers don't always pay enough attention to installation issues. And with some, fit is really bad. Remember, headers call for header bolts, not peanut butter bolts from the hardware store. Header bolts have small heads for flange/tube clearance. Most header bolts have a 3/8-inch head.
Headers and exhaust systems have become something of a cliché because everyone talks about them, yet not enough of us know how to choose them. We select headers for all kinds of reasons, many of them having nothing to do with performance. These days, it's more about how they look against a cylinder head and valve cover versus how they perform.
And contrary to what you might believe, headers don't always improve performance. Sometimes, they hinder depending on design. If you're running the same headers on your 427W stroker that you had on the 351W it replaced, you don't have enough header. You need larger header tubes and collectors to handle the increased exhaust gas volume. By the same token, header tubes that are too large will rob you of torque because there needs to be back pressure to make torque depending on valve overlap.
Another important element to header design, aside from performance and good looks, is how they fit. You want an exhaust header that cannot be seen hanging below the car when you look at a side profile of your Mustang. Headers that scrape speed bumps are a bad idea. If you're building a weekend racer, low hanging collectors aren't as critical. For street use, it becomes annoying every time you broach a parking lot.
When you think of PerTronix, you think of innovative ignition systems and ignition retrofits for classic Mustangs. However, PerTronix also has its own header brand, Patriot Headers, and they have acquired a couple of reputable exhaust manufacturers in recent years-JBA Headers and Doug's Headers, which has been around since 1958 and trusted by untold thousands of enthusiasts, including Shelby American in the 1960s.
We spoke with Don Lindfors at PerTronix Performance Products Exhaust Group about choosing headers for Mustangs.
MM: What kind of header do you recommend for classic Mustangs?
DL: The first question you need to ask is why you want headers in the first place. Are you looking to improve mileage or increase power? Do you have a high-performance engine that needs increased exhaust flow, a different sound, etc.? The next thing is the intended use of the car. Is it a daily-driver, a full-blown racer, a street/strip car, or a lowered Pro Touring-type car. With these questions answered, you can make an educated decision as to what best fits your needs. We look at classic Mustangs separately from late-model Mustangs because there are some very important differences, including the fact that in most states classic Mustangs are exempt from emission laws so you don't have to be concerned with that.
The PerTronix Exhaust Group offers several different types of headers for classic Mustangs. Shorty headers improve performance with excellent ground clearance and are a great way to go for lowered cars and stock or mild engines. Long-tube Tri-Y headers were pretty much invented for Mustangs, and Doug's Headers was one of the first in this segment. Tri-Ys offer big boosts in power across the RPM range and slightly better ground clearance than a traditional four-tube header, plus Carroll Shelby used Tri-Ys on his legendary GT350s. Four-tube, full-length headers are the most common type of header. They make big horsepower gains including at high RPM, but they usually sacrifice ground clearance. There are also specialty headers for engine swaps in classic Mustangs.
Header Selection Tip
When...
Header Selection Tip
When you're shopping header gaskets, never do it on the cheap. Opt for the best header gasket money can buy-Fel-Pro or SCE. Because headers are challenging to service and install even under the best of circumstances, header gaskets need to last a long time. Also, when you're installing headers, make sure all contact surfaces are clean, then torque header bolts uniformly to proper specifications to ensure perfect sealing.
It might be over the top to...
It might be over the top to call the JBA Shorty header legendary, however, this is likely the most popular shorty header ever made because JBA, led by Ford enthusiast J Bittle, was there first with a great idea. Shorty headers eliminate many of the shortcomings associated with long-tube headers. There are no ground clearance issues, no interference with the clutch equalizer shaft, and less underhood heat. The JBAs shown here are ceramic coated in charcoal gray for good looks, durability, and less heat.
This is the #H-8433-1 ceramic-coated...
This is the #H-8433-1 ceramic-coated Patriot shorty header for classic Mustangs with 260/289/302 engines. They offer excellent value for the money.
Check out Doug's D627 long-tube...
Check out Doug's D627 long-tube header for 390/427/428 FE Mustangs. How's this for snazzy plumbing, with crossover tubes for bank equalization? This is the header Super Stockers used in the good old days to take several NHRA titles. Because they're ceramic-coated, heat is not an issue.
Here's a more traditional...
Here's a more traditional long-tube, ceramic-coated header from Doug's for '65-'73 small-block Mustangs. These headers tuck in close to the floor pan for exceptional ground clearance.
This is the Hooker Dark Side...
This is the Hooker Dark Side long-tube header for '65-'73 Mustangs with 260/289/302 engines. Shown here in black ceramic, this is a time-proven design that has been in production for as long as there have been Mustangs.
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.