Holden HQ HJ HX HZ WB 5.7L 6.0L 6.2L LS V8 Pacemaker Competition Headers PH5343

Pacemaker PH5343 Competition headers (extractors) are designed for Holden HQ, HJ, HX, HZ and WB LS V8 engine conversions.

Pacemaker lists PH5343 for 5.7L, 6.0L and 6.2L LS-family V8 engines, covering commonly used LS1, LS2 and LS3 conversion applications.

The tuned 4-into-1 Competition design uses large 48mm (1⅞") primary pipes and 76mm (3") outlets. Compared with the smaller-primary PH5342, PH5343 provides increased primary pipe capacity for modified and higher-output LS combinations.

IMPORTANT – LS conversions can vary depending on engine mounts, sump, steering, starter motor, transmission and engine position. Confirm your individual conversion configuration before ordering.

Please check availability and current lead time before ordering.

Key Features

• Competition performance header
• Tuned 4-into-1 design
• 48mm (1⅞") primary pipes
• 76mm (3") outlets
• Designed specifically for HQ-WB LS V8 engine conversions
• Suits 5.7L, 6.0L and 6.2L LS-family V8 engines
• Manual and automatic transmission compatible
• Power steering compatible
• Air conditioning compatible
• Oxygen sensor provisions incorporated into the headers

Construction

Pacemaker PH5343 uses a tuned 4-into-1 Competition configuration with large 48mm (1⅞") primary pipes feeding into 76mm (3") outlets.

The larger primary pipe diameter makes PH5343 particularly suited to modified and higher-output LS V8 combinations where increased exhaust-flow capacity is required.

Additional Options

Ceramic Coating: PHC40 ceramic coating may be available for improved heat management and corrosion resistance. Please contact Best Mufflers for current availability.

DSF138: Replacement LS exhaust manifold/header gaskets are available separately.

Vehicle Fitment

• Holden HQ: LS V8 conversion
• Holden HJ: LS V8 conversion
• Holden HX: LS V8 conversion
• Holden HZ: LS V8 conversion
• Holden WB: LS V8 conversion
• Engine Capacity: 5.7L / 6.0L / 6.2L LS-family V8
• Common Engines: LS1 / LS2 / LS3 and compatible LS-family applications
• Transmission: Manual / Automatic
• Drive: Rear-Wheel Drive
• Power Steering: Yes
• Air Conditioning: Yes

Pacemaker lists PH5343 as an HQ-WB LS V8 conversion header. These engines were not factory fitted to HQ-WB models, so vehicle year references relate to the chassis rather than the LS engine.

Header Specifications

• Part Number: PH5343 L/R
• Brand: Pacemaker
• Design: Tuned 4-into-1 Competition
• Primary Pipe: 48mm (1⅞")
• Secondary Pipe: N/A
• Outlet: 76mm (3")
• Power Steering: Yes
• Air Conditioning: Yes
• Oxygen Sensor: Yes
• EGR: N/A
• Replacement Gasket: DSF138
• Approximate Fitting Time: 2 hours

Fitment Notes

LS Conversion: PH5343 is specifically designed as a Competition LS V8 conversion header for the Holden HQ-WB chassis.

Engine Capacity: Pacemaker specifies 5.7L, 6.0L and 6.2L LS-family V8 engines.

Transmission: Suitable for manual and automatic transmissions.

Power Steering: PH5343 is power-steering compatible.

Air Conditioning: PH5343 is air-conditioning compatible.

Oxygen Sensors: PH5343 incorporates oxygen sensor provisions for LS engine management systems. Check oxygen sensor positioning and wiring clearance during installation.

Engine Mounts: Engine position is critical in an LS conversion. Engine mounts, sump configuration and associated conversion components can affect header clearance. Confirm that the mounting system being used is compatible before ordering.

Check clearance around the steering, starter motor, transmission, chassis rails, floor and other conversion components during trial fitting.

Protect painted surfaces during trial fitting and do not fully tighten the headers until all required clearances have been confirmed.

What's Included

• Pacemaker PH5343 left-side header assembly
• Pacemaker PH5343 right-side header assembly

Header bolts, gaskets and other installation hardware should not be assumed to be included unless specifically confirmed with the current kit before ordering.

Recommended With

• DSF138 LS exhaust manifold/header gaskets
• Suitable LS conversion engine mounts
• Suitable 3" intermediate pipes, joiners or exhaust adaptors
• Professional exhaust system fabrication where required

PH5343 vs PH5342

PH5343: Competition 4-into-1 design with larger 48mm (1⅞") primary pipes and 76mm (3") outlets.

PH5342: Tuned 4-into-1 design with smaller 44mm (1¾") primary pipes and 76mm (3") outlets.

Both are designed for HQ-WB LS V8 conversions and suit 5.7L, 6.0L and 6.2L applications. The principal difference is the primary pipe diameter, with PH5343 providing the larger 1⅞" Competition configuration.

Why Good Headers & Exhaust Systems Matter

At 4,000 rpm, a 5.7L LS V8 theoretically draws approximately 11,400 litres of intake air per minute at 100% volumetric efficiency and expels around 34,200 litres of hot exhaust gas per minute at approximately 600°C.

A 6.0L LS V8 theoretically draws approximately 12,000 litres of intake air per minute, while a 6.2L LS V8 theoretically draws approximately 12,400 litres per minute at the same engine speed. The corresponding illustrative hot exhaust volumes are approximately 36,000 and 37,200 litres per minute.

Actual airflow varies with engine capacity, RPM, volumetric efficiency, camshaft, cylinder heads, induction system and engine specification.

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

LS engine conversions can vary considerably. Before installation, confirm the engine mounts, sump, steering system, starter motor position, transmission and engine position used in the vehicle.

Trial fit both headers before completing the downstream exhaust system and check oxygen sensor positioning and wiring clearance.

Because PH5343 uses large 1⅞" primary pipes and 3" outlets, particular attention should be paid to clearance around the chassis, steering and transmission.

Professional installation is recommended, particularly where fabrication or engineering approval forms part of the LS conversion.

Warranty & Compliance

Pacemaker headers are covered against manufacturing defects subject to Pacemaker's current warranty terms and conditions.

Because PH5343 is intended for an engine conversion, the completed vehicle must comply with applicable Australian state or territory requirements relating to engine conversions, emissions, exhaust noise and vehicle modifications.

FAQ

What vehicles do PH5343 headers suit?
PH5343 is designed for Holden HQ, HJ, HX, HZ and WB LS V8 engine conversions.

What engines do PH5343 headers suit?
Pacemaker specifies 5.7L, 6.0L and 6.2L LS-family V8 engines, including commonly used LS1, LS2 and LS3 conversion applications.

Are PH5343 headers Competition headers?
Yes. Pacemaker identifies PH5343 as a 1⅞" 4-into-1 Competition header.

What size are PH5343 headers?
They use 48mm (1⅞") primary pipes and 76mm (3") outlets.

Will PH5343 fit an LS1?
Yes. The 5.7L LS1 is within the PH5343 application.

Will PH5343 fit an LS2?
Yes. Pacemaker lists 6.0L LS-family applications for PH5343.

Will PH5343 fit an LS3?
Yes. Pacemaker lists 6.2L LS applications and specifically identifies PH5343 for LS engine conversions.

Will PH5343 fit with air conditioning?
Yes. Pacemaker lists PH5343 as air-conditioning compatible.

Will PH5343 fit with power steering?
Yes. Pacemaker lists PH5343 as power-steering compatible.

Does PH5343 have oxygen sensor provisions?
Yes. Pacemaker specifies oxygen sensor provision for PH5343.

What gasket suits PH5343?
Pacemaker specifies DSF138.

What is the difference between PH5342 and PH5343?
Both are 4-into-1 HQ-WB LS conversion headers with 3" outlets. PH5342 uses 44mm (1¾") primaries, while PH5343 uses larger 48mm (1⅞") primaries and is designated by Pacemaker as a Competition header.

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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