Tight tuck four-tube headers offer a great solution for narrow frame rail street rods.

There are some obvious differences between the different styles and manufacturer’s headers, and some not so obvious differences between headers. Doug’s Headers website if full of information that addresses the common and uncommon questions that consumers have regarding exhaust headers. We’ve asked the same questions many times.

Tri-Y headers for muscle cars, trucks, and motorhomes, are designed to yield maximum power from off-idle to 4,500 RPM. This makes them well suited for applications demanding maximum mid-range torque.

Why is there such a big price difference between styles and brands of headers?

Doug’s Headers: Header development and design is complex and requires a substantial amount of time and resources to do the job right! 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.

Do all Doug’s headers have the same basic design?
DH: No, absolutely not. Doug’s headers are designed and built to fit each applications specific requirements. The headers design is dependent on the intended vehicle usage and emissions requirements. Doug’s headers utilize five types of header designs. The four-tube full length headers are typically used for higher RPM horsepower, but can also increase the mid range torque in applications were there is room to fit a long tube design. Tri-Y headers for muscle cars, trucks, and motorhomes, yield maximum power from off-idle to 4,500 RPM, making them well suited for applications demanding maximum mid-range torque with maximum fuel economy.

Four-tube stock manifold replacement headers are designed for easy installation and emissions compliance. The four-tube shorty headers provide improved ground clearance for popular muscle cars and street rods, and the four-tube tight tuck headers are the best solution for narrow frame rail street rods.

Four-tube full length headers for higher horsepower applications.

Are flange and tubing thickness important to header performance?

DH: Absolutely! A properly machined and finished header flange eliminates annoying exhaust leaks which lead to horsepower loss. Doug’s headers utilize 3/8-inch flanges on passenger car and street rod applications and 1/2-inch to 5/8-inch flanges on heavy-duty applications, such as motorhomes and late model trucks. Thicker flanges hold up to heat better and are less likely to warp.

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.

What kind of performance gains can be expected by installing a set of headers?

DH: The addition of a set of headers typically adds 15-20% more horsepower and torque.  How much performance is gained depends on the condition of your vehicle and any additional upgrades you have made to the engine. All of our headers are designed and tested with appropriately sized tube diameters and lengths to bring you maximum performance and engine efficiency.

Four-tube shorty headers provide improved ground clearance for muscle cars and street rods.

When choosing a header, how do I know what primary and collector diameter size is best for my application?

DH: The best way to determine what size is best for your application depends on the purpose your vehicle. For daily drivers or engines that reside at low RPM ranges, smaller primary tube and collector diameters provide more low-end performance. Generally speaking the larger tube and collector diameters increase your horsepower and torque at higher RPM levels and are usually recommended for street/strip or race only applications.

Four-tube manifold replacement headers are designed for easy installation and emissions compliance.

What modifications are necessary to make these headers fit?

DH: Our product development department takes a substantial amount of time and effort to design our headers, so you don’t have to make modifications. We do not custom build headers, however, we do offer a complete line of do-it-yourself components for fabricating your own headers and exhaust systems, if you need custom-fit components.