Header Facts
Header development and design is complex and requires a substantial amount of time and resources to do the job right! Many manufacturers are unwilling to make the commitment and instead offer compromised headers at lower prices.
Doug’s will not compromise performance, quality or fit to compete with inferior designs at cheap prices. Every Doug’s header is tuned with the proper tube size and length to efficiently remove all the exhaust from each cylinder, reducing pumping losses resulting in a dramatic increases in horsepower and torque. Doug’s headers are carefully developed on the vehicles they are intended to fit and are re-checked numerous times during the design and manufacturing process.
Not all Doug’s headers use the same design. The type of header design will change depending on the intended vehicle usage and emissions requirements. Doug’s headers for conventional V-8 applications utilize five types of header designs:
Tubing and flange thickness
A properly machined and finished header flange eliminates annoying exhaust leaks which lead to horsepower loss. Doug’s headers utilize 3/8” flanges on passenger car and street rod applications and 1/2” to 5/8” flanges on heavy-duty applications, such as motorhomes and trucks. Thicker flanges hold up to heat better and are less likely to warp. Late model vehicles and high performance muscle cars produce super heated conditions that can warp “thinner” flanges. Header tubing thickness and proper fixture welding techniques can affect the longevity of a header. Headers for light duty applications are built with 16 gauge tubing. Heavy-duty applications, such as motorhomes or tow vehicles demand thicker 14 gauge tubing. Doug’s headers are built in heavy duty jig fixtures which eliminate heat distortion and movement of the individual header tubes. Each header is welded using cyclical welding techniques which reduces tube distortion.
What is included with a set of Doug's headers?
Every Doug’s header comes with all the necessary mounting hardware, collector reducers or connector pipes, premium gaskets and detailed installation instruction sheets. Our extra thick gaskets are rated up to 1100º F, pressures to 3700 psig (255 bar), and are designed for an exact port match with Doug’s headers. We do not recommended the use of other aftermarket gaskets.
Coated headers
Metallic Ceramic Thermal Barrier Coating (MCTBC), is simply the best header finish on the market and comes standard on all Doug’s headers. MCTBC protects and extends the life of headers by creating a thermal barrier that significantly lowers underhood temperatures and protects the substrate metal from thermal fatigue. After MCTBC is applied, it is polished with a vibratory finishing process that produces a high luster aluminum appearance. This coating is easy to maintain and will not change color under normal operating conditions. The polishing process compresses and activates the coating, which increases the surface hardness to produce a finish that is 60% more corrosion resistant than non-polished satin finishes.
Header Installation
Header installation for the most part can be accomplished with simple hand tools, a floor jack and jack stands. Some applications can be very time consuming due to limited space in the engine compartment. Should you encounter a fitment problem do not attempt to modify or alter the header in any way or your warranty will become void. Call our knowledgeable technical staff for assistance.