Holden V8 308/304/5.0L Billet Steel 4-Bolt Main Caps – Set of 3 | Splayed Design

💪 Reinforce Your Holden V8 for Serious Power

Did you know that factory 2-bolt main caps in Holden 308/304/5.0L engines often begin to fail around 450–500 HP (335–375 kW)? At these levels, cast caps can flex, walk, or crack under load — risking catastrophic bottom-end failure. If you’re targeting this range or beyond, billet splayed 4-bolt caps are cheap insurance to keep your Holden V8 alive.

When building a high-performance Holden 308, 304, or 5.0L engine — especially for boost, track, or hard street use — factory main caps can become a weak link. This 3-piece Billet Steel Main Cap Set delivers the strength, stability, and precision needed to hold bottom-end integrity at high power levels.

🔧 Why Upgrade to Billet Main Caps?

• OEM cast caps flex under load and high RPM
• Billet caps reduce crank movement and cap walk
• Cheap insurance for turbocharged, stroked, or high-revving Holden V8 builds

✅ Key Features:

• 3-piece billet steel main cap set – replaces factory caps
• Splayed 4-bolt design for improved block rigidity
• Zinc-coated for corrosion protection and longevity
• Precision CNC-machined in South Australia
• Built by Milton Engine Developments – trusted by performance engine builders nationwide

📦 Fitment:

• Holden 308 V8
• Holden 304 V8
• Holden 5.0L EFI engines

🔧 Installation Notes:

• Line boring required after installation
• ARP main studs recommended for best results
• Installation should be performed by a qualified engine builder or machine shop

🇦🇺 Australian Made by Milton Engine Developments

All main caps are engineered and CNC-machined in-house in South Australia by Milton Engine Developments — trusted across the country for precision race engine parts.

📦 Stock & Support

Stocked and shipped from Adelaide. On a tight timeline? Contact us to confirm lead time or to request additional machining services.