Chevy Header And Exhaust Tech - CHP Insider

Dan Lemons Of Lemons Headers Breaks Down Header Design And Exhaust Science

Stephen Kim Aug 1, 2008 0 Comment(s)
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Since most enthusiasts have better things to do with their time than fix header leaks, using the right gasket and installing it properly is critical. Ideally, a header-flange gasket should have openings larger than the exhaust ports to ensure the gasket will not obstruct exhaust flow. "We have had great success with copper gaskets, since they're extremely flat, which promotes an excellent seal, and do not expand or contract as much as fiber gaskets," Lemon says. "Copper can't crush like a fiber gasket, so we recommend using a thin layer of copper silicone on each side of the port opening."

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When in doubt, frustrated wrenchers turn to their trusty hammers. Fortunately, Lemons says there's nothing wrong with dimpling a header to simplify installation. "Making a small flat spot in a tube probably has a minimal effect on performance, but I wouldn't do it if you don't have to," he advises. "If your header is touching the steering column, for instance, there may be a way to adjust the column outward. If it's the starter that's in the way, you may have to use a mini starter. If you are trying to use a header made for a stock configuration on a tall-deck block or a raised-port head, then take a hammer with you."

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Design Parameters
"Designing a header that installs easily is a blessing, but we won't sacrifice performance or fitment to make a header easier to install," Lemons promises. "Some of our headers are a pain to install, but once they're in they fit well, have good spark plug access, and have plenty of ground clearance and room around the oil pan. All our race headers are made with individual tubes and slip-on collectors, so you install one tube at a time and the collectors slip on and bolt in place. This makes all the difference in the world. Many of these headers can be installed in 15 minutes with the engine and starter in place."

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Everyone seems to have a different theory on how to prevent header bolts from backing out, but here are some suggestions straight from an expert. "There are header bolts with locking washers that work well if you need them, and if your headers have extra-thick flanges, be sure to use bolts that are extra long," says Lemons. "The combination of heavy-duty header flanges and flat copper gaskets doesn't expand and contract like thin flanges and fiber gaskets, which virtually eliminates the potential for bolts to loosen over time. Once the headers are installed and the engine is started, always retighten the header bolts after the engine is warmed up."

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Ceramic coatings do a great job of keeping underhood heat down. Header wrap can work very effectively as well. One fact that is often overlooked, however, is that a properly sized header can make a big difference. "If your header is too small for your engine, then the header and the engine can overheat," Lemons says. "This is especially true with blower motors."


Lemons Headers


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