Performance Headers EXT511 — Holden Torana LH LX 350–383 Small Block Chev

The EXT511 performance exhaust headers are engineered for Holden Torana LH and LX models running performance 350 or 383 Small Block Chev (SBC) V8 engines. Designed as an interference-style system, these headers are suited to modified engines producing strong mid-to-high RPM power.

Vehicle Compatibility

• Holden Torana LH
• Holden Torana LX
• Engine: 350 SBC
• Engine: 383 Stroker SBC

Header Design

• Interference design for modified high performance engines
• Optimised for high-flow cylinder heads and larger camshaft combinations
• Mandrel bent for consistent internal diameter
• Precision formed collectors for smooth gas transition

Pipe Specifications

• Primary Pipes: 1.58"
• Secondary Pipes: 2.00"
• Collector Outlet: 2.50"

Why Good Headers and Exhaust Systems Matter

On average, a 5.7L (350ci) Small Block Chev engine draws ~11,400 L of air per minute and expels ~34,200 L per minute at 4000rpm [@600°C]

At 5000rpm, a well-built 350 SBC engine draws ~14,250 L of air per minute and expels ~42,750 L per minute [@600°C]

A 383 stroker increases displacement and airflow demand further, requiring efficient primary and collector sizing to maintain exhaust velocity and support high-RPM scavenging. The 1.75" primary and 2.25" secondary combination feeds into a 3.00" collector, allowing strong cylinder evacuation and improved top-end horsepower while maintaining mid-range torque.

Gaskets

Recommended gasket: DSF009

Important Notes

• Made to Order 6-8 week [approx] 
• Not suited to raised port cylinder heads
• Vehicle modifications may be required
• Professional installation recommended
• Remote oil filter recommended
• Not suited to 6.0L engine sump

What’s Included

• 1 x Custom SBC Headers EXT511

Customer Support

For phone orders, advice, or part enquiries – contact us:

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Exhaust Systems Since 1983