Big Block 496 8.1L All Stainless Steel Mercury Polished
For those of you searching for a superb value in a long tube
Stainless Steel header, this is it! The Magnum Stainless Steel header uses Mandrel
bent 316L stainless steel on the interior and exterior tubes. The header is tig welded with a custom alloy welding rod to help
prevent cracking. After assembly the entire header is stress relieved, annealed,
and heat-treated to maximize its corrosive resistance. The standard finish is satin and polishing is available as an option.
The system is sold with gaskets, bolts, and hardware.
EFI applications require ECU reprogramming.
When comparing performance exhaust systems it's good to understand the different systems on the market today and the performance demands of your
engine. Understanding how a header works will help you decide on which exhaust system is best suited for your application.
Headers have two basic functions. First is to simply relieve back pressure. For example, when looking at a manifold you see a 4" diameter exhaust hose, but the
actual exhaust gas opening is about 2-1/2" diameter. Most performance manifolds and some header manufacturers use a 4" exhaust hose and 3" or 3-1/2" OD exhaust
gas tube. All of these headers use a 4" OD exhaust gas tube and a 5" water jacket tube until the water gets introduced into the exhaust gas stream, then it gets
reduced from 5" to its 4" exhaust hose diameter. At no time does the exhaust gases see a diameter smaller than 4" OD. When looking at these exhaust gas openings
consider their area not their diameter. For example, a 4" OD opening has an area of approximately 12.56 sq. in. A 3-1/2" opening has an area of approximately 9.62 sq. in.
That is 25% smaller! A 3" opening is approximately 7.06 sq. in. and a 2-1/2" opening is approximately 4.90 sq. in. which is 60% smaller.
LIGHTNING HORSE POWER COMPARISON
Performance figures on headers vary considerably. As a rule, the higher horsepower engines benefit more than the lower horsepower engines. For example, the 330
hp Mercury engine will gain approximately 50 to 75 rpm, where as the 365 hp Mercury engine will gain approximately 300 to 400 rpm (45 hp). Blown engines gain up
to 800 rpm (80 hp). Of course this is comparing these headers against stock Mercury center rise manifolds.
ALL THIS PLUS THE BEST 2-YEAR WARRANTY IN THE INDUSTRY