Standard Jacketed Header - 496 8.1L Mercury 37

Standard Jacketed Header - 496 8.1L Mercury 37" Wide

Standard Jacketed Header - 496 8.1L Mercury 37" Wide Black Finish

These headers are designed to be a replacement for Mercury, OMC or jet manifolds. However, they terminate approximately 8" aft of stock manifolds and are projected to meet the exhaust tips providing they are in the stock location. Headers will have about 1/2" clearance between header and tall Moroso valve covers. Headers come complete with bolts, gaskets, water fittings, pet cocks, etc. (less 4" hose and 4" hose clamps). Factory oil filter requires relocation.

LIGHTNING PERFORMANCE
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.

LIGHTNING CONSTRUCTION
Our Magnum header starts with Mandrel bent 316L stainless steel interior tubes. The exterior tubes are Mandrel bent heavy wall steel tube (.074). The tubes are then mechanically etched by sand blasting and then assembled. Finally, a corrosion resistant silicone ceramic coating is applied to the interior of the header while the exterior receives a powder coat finish.

ALL THIS PLUS THE BEST 2-YEAR WARRANTY IN THE INDUSTRY

Through continuing research Lightning Mfg. has developed a Dual Porcelain Coating that resists the harshest of salt water environments. Now as an option they are able to apply the same high tech coating to a 316L stainless steel lined header once thought to be the cracking alloy and render it crack resistant.

Your Price: $2,399.99 
Part Number: 310-40308

496 Mag/HO B/B Chevy 8.1 Liter Mercury 37

496 Mag/HO B/B Chevy 8.1 Liter Mercury 37" Wide Freshwater Headers

496 Mag/HO B/B Chevy 8.1 Liter Mercury 37" Wide Freshwater Kit (Silver Finish)

THE ULTIMATE "FRESH WATER" EXHAUST SYSTEM

Finally an affordable alternative to all stainless steel water jacketed headers. For the thousands of pleasure boaters "NOT" affected by the corrosion problems associated with Salt Water there is at last the availability of a true tubular header system for the Fresh Water boater. These headers are designed to be a replacement for Mercury, OMC or jet manifolds. However, they terminate approximately 8" aft of stock manifolds and are projected to meet the exhaust tips providing they are in the stock location. Low Port Headers are also available for under the swim step applications. Standard width headers will have about 1/2" clearance between header and tall style Moroso valve cover. Headers come complete with bolts, gaskets, water fittings, pet cocks, etc. (less 4" hose and 4" hose clamps). Factory oil filter requires relocation.

THE LIGHTNING CONSTRUCTION DIFFERENCE IS WHAT COUNTS !
Our Magnum header starts with Mandrel bent 316L stainless steel interior tubes. The exterior tubes are Mandrel bent heavy wall steel tube (.074). The tubes are then mechanically etched by sand blasting and then assembled. Finally, a corrosion resistant silicone ceramic coating is applied to the interior of the header while the exterior receives a powder coat finish.

ALL THIS PLUS THE BEST 2-YEAR WARRANTY IN THE INDUSTRY

Through continuing research Lightning Mfg. has developed a Dual Porcelain Coating that resists corrosive water environments. Now able to apply the same high tech coating to the fresh water series of steel outer lined thus aiding in the prevention cracking and deterioration.

At last the easiest to install and most rewarding horsepower upgrade is now available for your 496 MAG and 496 HO mercury engine. Starting with the same superior production found in all lightning header Lightning has constructed a water-jacketed header designed as a direct replacement for the factory style 496-engine assemblies. Each header feature 2" id primary tubes mated to an oversized 5’ inlet collector reduced to accept the 4" factory hose connection. Simple incredible power gains have been achieved with just this simple installation. Improved throttle response as well as fuel efficiency are also a plus. Each system comes with the necessary accessory relocation hardware.

NOTE: Fuel pressure adjustments may be required.

50 To 60 Horsepower Gains have been reported with tubular header installation on the 496.

Your Price: $2,399.99 
Part Number: 310-40208

Big Block 496 8.1L All Stainless Steel Mercury Headers

Big Block 496 8.1L All Stainless Steel Mercury Headers

Big Block 496 8.1L All Stainless Steel Mercury Standard Satin Finish

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.

LIGHTNING PERFORMANCE
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

Your Price: $3,499.99 
Part Number: 310-40309

Big Block 496 8.1L All Stainless Steel Mercury Headers

Big Block 496 8.1L All Stainless Steel Mercury Headers

Big Block 496 8.1L All Stainless Steel Mercury Polished Finish

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.

LIGHTNING PERFORMANCE
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

Your Price: $4,099.99 
Part Number: 310-40316