Chrysler Slant 6 225 Billet Main Cap Set – Strength Upgrade for High-Performance Builds

🛠️ Strengthen Your Chrysler Slant 6 Engine — Built for Boost & RPM

Did you know the factory cast main caps in a Chrysler Slant 6 typically start to fail around 300–350 HP (225–260 kW)? At this level the OEM caps can crack, walk, or lose alignment under load — especially with boost, nitrous, or high RPM use. If your build is aiming for this range or beyond, upgrading to billet main caps is cheap insurance to protect your investment.

When building serious horsepower into a Chrysler 225ci Slant 6 engine — especially with forced induction, strokers, or sustained high-RPM use — the factory cast main caps become a critical weak point. This billet 4-cap upgrade delivers the stability and alignment required to push your build further with confidence.

Manufactured by Milton Engine Developments, these billet main caps are precision CNC-machined in South Australia and zinc-coated for long-term protection, delivering reliability and performance trusted by race engine builders across Australia and beyond.

💪 Why Upgrade to Billet Main Caps?

• OEM cast caps can flex or shift under load, risking crank walk and bearing wear
• Billet caps ensure greater strength, alignment, and bottom-end rigidity
• Essential for high-boost, stroker, nitrous, and high-RPM engine builds

✅ Key Features:

• 4-piece billet steel main cap set – replaces all factory caps
• Precision CNC-machined in South Australia
• Zinc-coated for corrosion resistance and durability
• Designed for maximum bottom-end strength
• Requires line boring after installation

📦 Fitment:

• Chrysler Slant 6 225ci (3.7L) inline-6 engines
• Fits Australian models: Valiant Charger, Valiant Pacer, Valiant Regal
• Fits U.S. models: Dodge Dart, Dodge Demon, Dodge Aspen
• Fits U.S. models: Plymouth Duster, Barracuda, Valiant, Scamp, Fury (select trims)
• Suited to builds from the 1960s through 1980s

🔧 Installation Notes:

• Line boring/honing required after installation
• ARP main studs or bolts recommended
• Must be installed by a qualified machine shop or engine builder

🇦🇺 Proudly Made in Australia

All billet main caps are engineered and CNC-machined by Milton Engine Developments in South Australia — trusted by engine builders and racers nationwide.

⏱️ Time-Sensitive Build? Contact us before purchase to confirm current lead times.
📩 Need a Custom Solution? We can manufacture billet caps for engines not listed — just reach out.