EXT393 Performance Headers – Toyota Soarer & Lexus SC400 4.0L V8 1UZ-FE (inc VVT-i) 1991–2000

EXT393 long tube performance headers (extractors) are designed for Toyota Soarer and Lexus SC400 models fitted with the 4.0L 1UZ-FE V8 (inc VVT-i) from 1991 to 2000. These precision-engineered headers improve exhaust flow, increase usable torque, sharpen throttle response, and deliver a stronger V8 exhaust note.

Ideal for restorations, street-performance vehicles, and weekend cruisers, the EXT393 headers provide a durable and tidy performance upgrade over the restrictive factory exhaust manifolds. Best Mufflers provides expert advice and shipping across Australia.

Key Features

• Interference-design headers recommended for street-performance applications
• 42mm mandrel-bent primary pipes
• 45mm secondary pipes
• 63mm / 2.50-inch flanged outlets
• Thick machined flanges for durability and reliable exhaust sealing
• Oxygen sensor fittings included
• Smooth merge collectors for improved exhaust scavenging and power delivery
• Designed to improve torque, throttle response, and exhaust note
• Check availability before ordering 

Construction

• Manufactured from high-quality steel tubing
• Quality welded construction for strength and long service life
• Heat-resistant painted finish rated to approximately 800°C
• Precision-formed pipes and collectors for consistent fitment and flow

Additional Options

• Ceramic Coating: Available as an optional upgrade for improved heat management, corrosion resistance, and appearance
• Cylinder Head Gaskets: DSF818 exhaust manifold gaskets are available separately for reliable sealing
• Exhaust Connection: Matching intermediate pipes, flanges, joiners, or adaptors may be required depending on the existing exhaust system

Fitment Notes

• Designed for Toyota Soarer and Lexus SC400 models fitted with the 4.0L 1UZ-FE V8 (inc VVT-i)
• Suitable for applicable vehicles manufactured from 1991 to 2000
• Will fit left-hand-drive vehicles
• Will fit vehicles with factory air conditioning
• Confirm steering-shaft, engine-mount, transmission, and chassis clearance before final installation
• Clearance may vary where non-standard engine mounts, steering components, transmissions, or suspension parts have been fitted
• Professional installation and exhaust fabrication may be required to connect the headers to the existing exhaust system
• Protect painted surfaces and carefully wrap the headers during trial fitting to prevent finish damage
• Do not run the engine for extended periods until the complete exhaust system is connected
• Verify emissions, noise, and vehicle registration compliance in your state or territory before installation

Why Good Headers & Exhaust Systems Matter

• At 4,000 rpm, the 4.0L 1UZ-FE V8 moves approximately 8,000 litres of intake air per minute and expels around 24,000 litres of exhaust gas per minute at approximately 600°C.
• At 6,000 rpm, airflow increases to approximately 12,000 litres of intake air per minute and around 36,000 litres of exhaust gas per minute.
• Efficient headers and a correctly sized exhaust system help reduce restriction, improve exhaust scavenging, strengthen torque delivery, and maintain performance as engine speed increases.

What’s Included

• EXT393L left-side performance header
• EXT393R right-side performance header
• Outlet flanges
• Outlet flange bolts and gaskets
• Oxygen sensor fittings incorporated into the headers

Recommended With

• DSF818 cylinder head exhaust gaskets
• 63mm / 2.50-inch intermediate exhaust pipes
• Matching exhaust flanges, joiners, clamps, and adaptors
• High-flow catalytic converters and mufflers where suitable
• New exhaust mounting rubbers and hardware where required

Warranty & Compliance

• Backed by a manufacturer’s two-year warranty; standard warranty terms and conditions apply
• Warranty applies to the supplied parts and does not cover labour, freight, removal, refitting, or consequential costs
• Painted header finishes are intended to protect the product during storage and transport and may require refinishing after installation
• Correct installation, adequate clearance, proper engine tuning, and secure exhaust support are essential for warranty coverage
• Check local regulations for emissions, noise, roadworthiness, and registration compliance before installation

Frequently Asked Questions

Will EXT393 headers fit both the Toyota Soarer and Lexus SC400?

Yes. EXT393 headers are designed for applicable Toyota Soarer and Lexus SC400 models fitted with the 4.0L 1UZ-FE V8 engine from 1991 to 2000. Confirm your vehicle, steering position, engine, transmission, and existing modifications before ordering.

Are these long tube performance headers?

Yes. EXT393 uses a long tube interference design intended for street performance to improve exhaust scavenging, usable torque, throttle response, and exhaust flow compared with the factory exhaust manifolds.

Will these headers fit left-hand-drive vehicles?

Yes. These headers are listed as suitable for left-hand-drive applications. Clearance should still be checked where the vehicle has modified steering components, engine mounts, suspension, or drivetrain parts.

Will they fit with factory air conditioning?

Yes. The EXT393 headers are designed to fit vehicles retaining the factory air-conditioning system.

Do the headers have oxygen sensor fittings?

Yes. Oxygen sensor fittings are incorporated into the headers. Confirm the sensor position and wiring clearance during installation.

Are cylinder head gaskets included?

Outlet flange gaskets and hardware are supplied. DSF818 cylinder head exhaust gaskets are available separately and are recommended to help achieve a reliable seal.

Will the headers connect directly to the factory exhaust system?

Exhaust fabrication or intermediate connection pipes may be required. The headers have flanged 63mm / 2.50-inch outlets, and the final connection will depend on the vehicle’s existing exhaust system.

Can these headers be ceramic coated?

Yes. Ceramic coating is available as an optional upgrade and can improve corrosion resistance, reduce radiant under-bonnet heat, and provide a more durable appearance.

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, advice, or part enquiries – contact us:

🇦🇺 Best Mufflers
87A Planthurst Road, Carlton NSW 2218
Mon–Fri 8:00am–5:00pm (by appointment only)