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Hedders are specially designed tubular manifolds which replace the inefficient heavy factory cast iron manifolds.
Hedman Hedders increase performance and economy by improving the efficiency of a car's engine. They accomplish this by removing the exhaust gases faster and more efficiently than stock manifolds. Stock manifolds are designed for low cost. They have a short, cramped design which causes some exhaust gas to get bottled up in the cylinder. Because of these residual exhaust gases in the cylinder, the size of the new fuel charge is limited and engine temperature is increased.
Hedman Hedders have smooth, contoured individual pipes for each cylinder. These primary pipes create a suction effect, called scavenging, which sucks the exhaust gases out. This creates additional velocity in the cylinder and actually helps to pull in the fresh air fuel charge.
You betcha! Hedders were originally developed for racing applications and Hedman Hedders are carefully designed to provide maximum increased power for passing, hauling loads, towing, etc. In some cases, this extra power contributes directly to improved economy because the engine does not have to work or labor as hard to pull a heavy load or conquer steep grades.
In today's economy, cost is of great concern. Why not get the most performance for your dollar? The highest gain in performance is simply done by installing a quality set of Hedman Hedders. Why? Hedman Hedders allow an engine to breathe more efficiently letting it work easier to produce more horsepower which allows cooler engine temperatures and better drivability.
No, definitely not. Each Hedman Hedder is designed for a specific application. The length and diameter of the primary tubes and the collector size vary according to the size, weight, transmission type, gear ratio and intended usage of the vehicle. A hedder for an RV camper will have relatively long, small diameter primary tubes and a modest sized collector. On the other hand, a race car hedder will often have large primaries and a much larger collector. The applications and usage are different so the hedders must be designed to differently to provide maximum efficiency are best results.
If you are planning on using aftermarket or newer heads, you ALWAYS want to start by finding a set of Hedders that are designed to fit the chassis as well as the heads you plan on using first. Most aftermarket racing heads have raised exhaust ports, slightly different sparkplug angles and/or a modified exhaust port exit angle. Even if a head manufacturer refers to their product as "same as stock", and the bolt holes may line up, even the slightest deviation from the factory head's specs will change the position of the header tubes and collector, causing interference.
The animation on this page is a very simplified demonstration of what happens when even the SLIGHTEST differences are present. Although the diagram only references a starter and mounts, other items that can interfere include the bell housing, power steering box, steering shaft, frame rails, wheel well, etc.
Most Hedman Hedders are designed around the stock heads (unless specified), and are not compatible with many aftermarket heads.
If you have aftermarket heads, we recommend you contact our tech department by EMAIL or by phone to see if the header you are interested is compatible with the heads you want to use. You should also check out our Hedman Husler Line of Headers. Many Husler Hedders are designed specifically for use with many popular aftermarket heads.
The spark plug orientation on Ford's GT40P heads differ greatly from standard GT40, or factory style heads. This causes primary tube interference with the plugs, deeming our headers unusable on GT40P heads.
SHORT ANSWER: NO. Hedman's can not be used with GT40P heads.
Hedders reduce engine temperatures in two ways. By increasing the speed with which super heated exhaust gasses are drawn out of the cylinder, the hedder reduces heat buildup. In addition, the increased volume of the fresh fuel charge due to scavenging acts as a further cool agent. A cooler combustion chamber and cylinder provide for a denser fuel charge which in turn creates more power. The lower temperature also acts to reduce the chance of pre-ignition or "knock".
Hedman does not recommend these products be used on our hedders. The reason? These products are designed to hold the extreme engine temperature inside the hedder. By doing so, the cool air is not allowed to circulate around the external surface of the tubular construction. Thus the internal temperatures reach extremely high temperatures to almost molten stages causing the hedder to become highly fatigued which will cause hedder failure. This will void your warranty!
Hedman offers the most significant improvement since the creation of performance hedders. HTC. Hedman Hi-Tech Coating. This revolutionary finish is guaranteed to protect your Hedman Hedders from external rust-through for the entire life of the hedder and it's high luster finish gives you a quality appearance.
Hedman Hedders are designed for the easiest possible installation. Almost any muffler shop can do the job or you can do it yourself using only a few simple hand tools, a jack, and some car stands. To make it easy, Hedman includes detailed, easy to follow, step-by-step installation instructions with each set of hedders.
Hedman Hedders are built to last using the finest materials and manufacturing procedures. That's why each new Hedman Hedder is covered by a lifetime guarantee against defects in workmanship or materials.
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