Mitsubishi Sigma GE GH GJ GK GN 1977-1987 2.0L 2.6L Astron Advance Exhaust Headers A342

Advance A342 headers (extractors) are designed for selected Mitsubishi Sigma GE, GH, GJ, GK and GN rear-wheel-drive models from 1977-1987 fitted with the 2.0L 4G52 or 2.6L 4G54 Astron four-cylinder petrol engine.

These Australian-made headers feature a heavy-duty press-bent design and provide a performance-oriented replacement for the original exhaust manifold, helping improve exhaust flow, torque, throttle response and engine performance.

Bolts and gaskets included.

Please check availability and current lead time before ordering.

Key Features

• Suits selected Mitsubishi Sigma GE, GH, GJ, GK and GN models
• Suits 2.0L 4G52 Astron SOHC petrol engine
• Suits 2.6L 4G54 Astron SOHC petrol engine
• Heavy-duty construction
• Press-bent header pipes
• Designed for rear-wheel-drive Astron applications
• Bolts and gaskets included
• Australian Made

Construction

Advance A342 headers feature heavy-duty press-bent construction developed for durable street use.

Unlike a mandrel-bent pipe, a press-bent pipe reduces slightly through the bend. This traditional header construction has been widely used on Australian street-performance exhaust systems and provides a strong, durable header assembly.

Additional Options

Please contact Best Mufflers for current availability and advice regarding compatible exhaust components for your Mitsubishi Sigma.

Vehicle Fitment

• Make: Mitsubishi / Chrysler
• Model: Sigma
• Series: GE / GH / GJ / GK / GN
• Overall Application Range: 1977-1987
• Engine: 2.0L / 1995cc 4G52 Astron
• Engine: 2.6L / 2555cc 4G54 Astron
• Engine Type: SOHC four-cylinder petrol
• Drive: Rear-wheel drive

Engine Year Note: The overall A342 Sigma application spans 1977-1987, but both engine sizes were not available throughout that entire period. The 2.0L 4G52 was available from the GE Sigma introduced in 1977, while the 2.6L 4G54 arrived later. The final GN Sigma continued with the 2.6L Astron II through 1987.

Header Specifications

• Part Number: A342
• Brand: Advance Headers
• Construction: Heavy duty
• Pipe Forming: Press bent
• Quantity: 1 header assembly
• Bolts: Included
• Gaskets: Included
• Manufacture: Australian Made

Fitment Notes

A342 is designed for rear-wheel-drive Mitsubishi/Chrysler Sigma models fitted with the longitudinal 2.0L 4G52 or 2.6L 4G54 Astron engine.

Confirm the engine and vehicle configuration before ordering. These vehicles are now several decades old and engine conversions, transmission changes and previous exhaust modifications are common.

What's Included

• 1 x Advance A342 header assembly
• Installation bolts
• Gaskets

Recommended With

Please contact Best Mufflers if you require advice on compatible exhaust components or replacement mounting parts for your Sigma.

Why Good Headers & Exhaust Systems Matter

The 2.0L 4G52 Astron engine theoretically draws approximately 4,000 litres of intake air per minute at 4,000 rpm at 100% volumetric efficiency. Using an illustrative hot exhaust volume at approximately 600°C, this represents around 12,000 litres of exhaust gas per minute.

The larger 2.6L 4G54 Astron theoretically draws approximately 5,200 litres of intake air per minute at 4,000 rpm, representing around 15,600 litres of hot exhaust gas per minute using the same illustrative calculation.

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

Professional installation is recommended. Check exhaust alignment and clearance around the steering, transmission, chassis and surrounding components before completing installation.

Lubricate threaded fasteners with WD-40 or a similar penetrating lubricant before removal to assist with easier removal and installation. After installation and several heat cycles, inspect the system for exhaust leaks and recheck accessible fasteners where appropriate.

Warranty & Compliance

Installation should comply with applicable Australian state or territory requirements relating to exhaust noise, emissions equipment where applicable, and vehicle modifications.

FAQ

Is this product currently available?
Availability and lead times can vary. Please check availability and current lead time before ordering.

What Mitsubishi Sigma models does A342 suit?
A342 is listed for selected GE, GH, GJ, GK and GN rear-wheel-drive Sigma models fitted with the 2.0L or 2.6L Astron engine.

Does A342 suit the 2.0L Sigma?
Yes. A342 is listed for the 2.0L 4G52 Astron engine used in selected Sigma models from the GE through to the early GN series.

Does A342 suit the 2.6L Sigma?
Yes. A342 is listed for the 2.6L 4G54 Astron used in selected Sigma models, including the later GN Astron II application.

Are these headers mandrel bent?
No. The supplied Advance A342 specification describes these headers as press bent.

Are bolts and gaskets included?
Yes. The supplied A342 product information specifies that bolts and gaskets are included.

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

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