Holden HQ HJ HX HZ WB 283-400 Small Block Chev V8 Pacemaker Headers PH5310

Pacemaker PH5310 headers (extractors) are designed for Holden HQ, HJ, HX, HZ and WB applications fitted with Small Block Chevrolet V8 engines.

Pacemaker lists PH5310 for 283, 302, 305, 307, 327, 350 and 400 Small Block Chev V8 engines. The Tri-Y design uses 41mm (1⅝") primary pipes, 51mm (2") secondary pipes and 57mm (2¼") outlets to provide a performance header solution for street, restoration and modified HQ-WB applications.

IMPORTANT – PH5310 will not fit slant-plug cylinder heads. For slant-plug heads, see Pacemaker PH5315.

PH5310 will not fit raised-port cylinder heads.

Correct engine mounting spacers are required. RH spacer is 1¾" high and LH spacer is 1¼" high.

Please check availability and current lead time before ordering.

Key Features

• Tri-Y header design
• 41mm (1⅝") primary pipes
• 51mm (2") secondary pipes
• 57mm (2¼") outlets
• Suits 283-400 Small Block Chevrolet V8 engines
• Manual and automatic transmission compatible
• Power steering compatible
• Air conditioning compatible
• Designed for Holden HQ-WB Small Block Chev applications

Construction

Pacemaker PH5310 uses a Tri-Y configuration with 41mm (1⅝") primary pipes feeding into 51mm (2") secondary pipes and 57mm (2¼") outlets.

The standard Pacemaker finish uses the distinctive Pacemaker Blue heat-resistant coating, designed to withstand temperatures up to approximately 800°C.

Additional Options

Ceramic Coating: PHC10 ceramic coating may be available for improved heat management and corrosion resistance. Please contact Best Mufflers for current availability.

DSF9: Replacement cylinder-head exhaust gaskets are available separately.

PEMP350: Pacemaker engine mounting spacers are available where the original correct engine spacers are not fitted.

Vehicle Fitment

• Holden HQ: Small Block Chevrolet V8
• Holden HJ: Small Block Chevrolet V8
• Holden HX: Small Block Chevrolet V8
• Holden HZ: Small Block Chevrolet V8
• Holden WB: Small Block Chevrolet V8 application
• Engine: 283 / 302 / 305 / 307 / 327 / 350 / 400 Small Block Chevrolet V8
• Transmission: Manual / Automatic
• Power Steering: Yes
• Air Conditioning: Yes

Pacemaker lists the PH5310 application as HQ-WB, 1971-1985. Engine availability varied between models and years, so the engine listing above should be treated as PH5310 header compatibility rather than factory engine availability for every HQ-WB model.

Header Specifications

• Part Number: PH5310 L/R
• Brand: Pacemaker
• Design: Tri-Y
• Primary Pipe: 41mm (1⅝")
• Secondary Pipe: 51mm (2")
• Outlet: 57mm (2¼")
• Power Steering: Yes
• Air Conditioning: Yes
• Oxygen Sensor: N/A
• EGR: N/A
• Replacement Gasket: DSF9
• Approximate Fitting Time: 2 hours

Fitment Notes

Slant-Plug Heads: PH5310 will not fit slant-plug cylinder heads. Pacemaker specifies PH5315 for slant-plug applications.

Raised-Port Heads: PH5310 will not fit raised-port cylinder heads.

Engine Mounting Spacers: PH5310 will only fit with the original engine mounting spacers or Pacemaker PEMP350 spacers. The spacers must be installed on the correct side of the vehicle:

• RH spacer: 1¾" high
• LH spacer: 1¼" high

Turbo 400: Pacemaker confirms PH5310 will fit the Turbo 400 automatic transmission.

Powerglide: Pacemaker confirms PH5310 will fit the Powerglide automatic transmission.

Column Automatic: Existing PH5310 application information specifies that column automatic linkages require modification. Check linkage clearance during installation.

Turbo 350: Existing PH5310 application information lists Turbo 350 compatibility. Pacemaker's current product page does not specifically mention Turbo 350, so confirm the individual vehicle configuration if clearance is uncertain.

Protect painted surfaces during trial fitting and check steering, starter motor, transmission, engine mounts, linkages and exhaust clearances before final tightening.

What's Included

• Pacemaker PH5310 left-side header assembly
• Pacemaker PH5310 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

• DSF9 exhaust manifold/header gaskets
• Pacemaker PEMP350 engine mounting spacers where required
• Suitable intermediate pipes, joiners or exhaust adaptors

Why Good Headers & Exhaust Systems Matter

At 4,000 rpm, a 350ci (5.7L) Small Block Chevrolet 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.

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

Before ordering, identify the cylinder-head type and confirm the engine uses standard-port, non-slant-plug heads.

Check that the correct engine mounting spacers are fitted. Pacemaker specifies a 1¾" RH spacer and 1¼" LH spacer, or the corresponding Pacemaker PEMP350 spacer kit.

On vehicles with a column-shift automatic transmission, check and modify the transmission linkage as required for header clearance.

Professional installation is recommended.

Warranty & Compliance

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

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

FAQ

What vehicles do PH5310 headers suit?
Pacemaker lists PH5310 for Holden HQ-WB Small Block Chevrolet V8 applications. The current Pacemaker specification covers the 1971-1985 HQ-WB platform.

What engines do PH5310 headers suit?
Pacemaker lists 283, 302, 305, 307, 327, 350 and 400 Small Block Chevrolet V8 engines.

Are PH5310 headers Tri-Y?
Yes. Pacemaker's current specification identifies PH5310 as a Tri-Y header.

What size are PH5310 headers?
They use 41mm (1⅝") primary pipes, 51mm (2") secondary pipes and 57mm (2¼") outlets.

Will PH5310 fit slant-plug cylinder heads?
No. Pacemaker specifies PH5315 for slant-plug cylinder-head applications.

Will PH5310 fit raised-port cylinder heads?
No. Pacemaker specifically states that PH5310 will not fit raised-port heads.

Will PH5310 fit with power steering?
Yes. Pacemaker lists PH5310 as power-steering compatible.

Will PH5310 fit with air conditioning?
Yes. Pacemaker lists PH5310 as air-conditioning compatible.

Will PH5310 fit a Turbo 400?
Yes. Pacemaker specifically confirms Turbo 400 automatic compatibility.

Will PH5310 fit a Powerglide?
Yes. Pacemaker specifically confirms Powerglide automatic compatibility.

What engine mounting spacers are required?
PH5310 requires the original correct engine mounting spacers or Pacemaker PEMP350 spacers. Pacemaker specifies RH 1¾" high and LH 1¼" high.

What gasket suits PH5310?
Pacemaker specifies DSF9.

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.

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