Jeep Cherokee XJ Grand Cherokee ZJ 4.0L 409 Stainless Headers – Wildcat WILD091SS

Wildcat WILD091SS 409 stainless steel exhaust headers (extractors) are designed for selected Jeep Cherokee XJ models from 1994–2001 and Jeep Grand Cherokee ZJ models from 1994–1998 fitted with the 4.0L inline 6-cylinder petrol engine, commonly known as the AMC 242 / Jeep 4.0L engine.

Manufactured from 409 stainless steel, WILD091SS provides increased corrosion resistance and excellent durability through repeated heating and cooling cycles. This makes 409 stainless steel particularly well suited to demanding exhaust applications including daily driving, touring and off-road use.

Featuring an interference-style header design, WILD091SS replaces the restrictive factory exhaust manifold with larger performance pipework. The combination of 1.50" primary pipes, 2.00" secondary pipes and a 2.50" outlet is designed to improve exhaust gas flow and scavenging, helping improve torque, throttle response and usable engine performance.

WILD091SS is designed as a direct bolt-on replacement for the applicable factory exhaust manifold.

MADE TO ORDER – WILD091SS headers are currently made to order and may take approximately 4–6 weeks. Please check availability and current lead time before ordering.

Key Features

• Designed for selected Jeep Cherokee XJ 1994–2001 models
• Designed for selected Jeep Grand Cherokee ZJ 1994–1998 models
• Suits the 4.0L inline 6-cylinder petrol engine
• Manufactured from 409 stainless steel
• Interference-style design for street, touring and off-road applications
• 1.50" (approximately 38mm) primary pipes
• 2.00" (approximately 51mm) secondary pipes
• 2.50" (approximately 63mm) outlet
• Direct bolt-on application
• Improved corrosion resistance compared with conventional mild steel headers
• Designed to improve exhaust flow, torque, throttle response and engine performance

Construction

• Australian-made Wildcat performance headers
• 409 stainless steel construction
• Strong welded construction for durability
• Designed to withstand repeated exhaust heating and cooling cycles
• Improved corrosion resistance compared with mild steel construction
• Heavy-duty cylinder-head mounting flange
• Raw stainless steel finish

Why 409 Stainless Steel?

409 stainless steel is widely used for automotive exhaust applications because it combines good high-temperature durability with improved corrosion resistance compared with conventional mild steel. It performs well through repeated heating and cooling cycles and is a practical material for headers and exhaust systems exposed to demanding road and off-road conditions.

Unlike 304 stainless steel, 409 stainless steel is magnetic and can develop surface discolouration or light surface oxidation over time. This is normal for 409 stainless steel and does not mean the material has lost its corrosion-resistant properties.

Additional Options

• DSF804G: Exhaust manifold/header gasket available separately
• Replacement manifold bolts and exhaust hardware where required

Vehicle Fitment

• Make: Jeep
• Model: Cherokee
• Series: XJ
• Year Range: 1994–2001
• Engine: 4.0L inline 6-cylinder petrol

• Make: Jeep
• Model: Grand Cherokee
• Series: ZJ
• Year Range: 1994–1998
• Engine: 4.0L inline 6-cylinder petrol

Fitment Notes

• Suits selected Jeep Cherokee XJ 1994–2001 4.0L applications
• Suits selected Jeep Grand Cherokee ZJ 1994–1998 4.0L applications
• Direct bolt-on replacement for the applicable factory exhaust manifold
• Vehicle modifications, engine conversions, engine mounts, steering components or non-standard exhaust systems may affect clearance and fitment
• WILD091SS is currently made to order and may take approximately 4–6 weeks
• Please check availability and current lead time before ordering.

What’s Included

• 1 x Set Wildcat WILD091SS 409 stainless steel headers / extractors
• HTG549 base gasket with bolts

Recommended With

• DSF804G exhaust manifold/header gasket for cylinder-head fitment
• Replacement manifold bolts and nuts where existing hardware is worn or corroded
• High-temperature exhaust sealant where required
• Quality performance exhaust system where further exhaust flow improvement is required

Why Good Headers & Exhaust Systems Matter

At 4,000 rpm, the 4.0L Jeep inline 6-cylinder engine draws in approximately 8,000 litres of intake air per minute and expels around 24,000 litres of hot exhaust gas per minute at approximately 600°C. A well-designed header and exhaust system helps manage this high gas flow efficiently, reducing restriction and improving exhaust scavenging, torque, throttle response and engine performance.

Installation Tips

Apply penetrating lubricant such as WD-40 or similar to the manifold bolts, nuts and exhaust fasteners before removal. Remove all traces of old gasket material and inspect the cylinder-head sealing surface before installation. Trial-fit the headers and check engine, steering, transmission and body clearance before final tightening. Ensure all gaskets and connections are correctly aligned and inspect existing mounting hardware for wear or corrosion.

After the initial heat cycles, inspect the installation and re-check the header fasteners to help maintain a reliable gasket seal.

Warranty & Compliance

Wildcat headers are covered by the applicable 2-year manufacturer's warranty against manufacturing and weld defects, subject to standard warranty terms and conditions. Incorrect installation, modification or damage caused during installation is not covered.

Installation must retain the catalytic converter, oxygen sensors and any other emissions-control equipment required for the vehicle. Exhaust and emissions requirements vary between Australian states and territories, and the completed installation must comply with the regulations applicable in your state or territory.

FAQ

What vehicles do WILD091SS headers suit?
WILD091SS is designed for selected Jeep Cherokee XJ models from 1994–2001 and Jeep Grand Cherokee ZJ models from 1994–1998 fitted with the 4.0L inline 6-cylinder petrol engine.

What is the difference between WILD091 and WILD091SS?
Both versions are designed for the same selected Jeep 4.0L applications. WILD091 is manufactured from mild steel, while WILD091SS is manufactured from 409 stainless steel for increased corrosion resistance and long-term durability.

Why use 409 stainless steel for exhaust headers?
409 stainless steel is well suited to exhaust applications because it provides good durability at elevated exhaust temperatures and improved corrosion resistance compared with conventional mild steel.

Will 409 stainless steel stay shiny?
Not necessarily. 409 stainless steel can develop surface discolouration and light surface oxidation after exposure to heat, moisture and road conditions. This is normal for 409 stainless steel and does not necessarily indicate structural corrosion.

Is 409 stainless steel magnetic?
Yes. 409 stainless steel is normally magnetic, so a magnet sticking to these headers does not mean they are made from ordinary mild steel.

Are WILD091SS headers direct fit?
Yes. WILD091SS is designed as a direct bolt-on replacement for the factory exhaust manifold on the applicable standard vehicle configuration.

What size are the WILD091SS header pipes?
WILD091SS uses 1.50" primary pipes, 2.00" secondary pipes and a 2.50" outlet.

What is supplied with WILD091SS?
WILD091SS is supplied as a 409 stainless steel header/extractor set with an HTG549 base gasket and bolts.

Which cylinder-head gasket is recommended?
The recommended exhaust manifold/header gasket is DSF804G, available separately.

Are WILD091SS headers made to order?
Yes. WILD091SS headers are currently made to order and may take approximately 4–6 weeks. Please contact us for current availability and lead time before ordering.

Are WILD091SS headers Australian made?
Yes. Wildcat WILD091SS headers are manufactured in Australia.

Can I pick up from the store?
Yes. Pick up is available but must be pre-arranged before collection.

How much is freight?
Freight varies depending on your delivery location and where stock is available. Please contact us for freight charges before ordering. Where possible, we can arrange dispatch from the nearest available product location to help reduce freight costs and delivery times.

Do you ship to the USA?
Yes. Best Mufflers regularly ships exhaust systems and exhaust parts to customers throughout the United States.

Please note that import duties, tariffs, taxes, and customs clearance fees are not included in the product or shipping price. Once your order is processed and the applicable charges are calculated, we will send you a secure payment link to finalise the import duties and tariff charges before dispatch.

Customer Support

For phone orders, fitment advice or product enquiries, contact Best Mufflers:

Call Now: +61 2 9547 3511 Email Us

Best Mufflers
87A Planthurst Road, Carlton NSW 2218, Australia
Monday–Friday 8:00am–5:00pm by appointment
Exhaust Systems Since 1983