5.9 Cummins Manifolds

Each high-flow cast manifold is engineered for optimal airflow and a precise fit on 1998–2007 Dodge Ram trucks. Options include direct-fit stock-replacement and performance configurations (T3/T4/T4i) to match your turbo setup and power goals.

Shop by 5.9 engine variant

• 12-Valve (1994–1998): Robust pulse energy for quick lighting with performance or towing turbos.
• 24-Valve VP44 (1998.5–2002): Popular street/tow choice; improved flow lowers drive pressure.
• Common-Rail (2003–2007): Smoother runners and proper collector geometry support clean combustion and response.

What is the purpose of the exhaust manifold

The exhaust manifold collects cylinder pulses and directs them to the turbine. Proper runner sizing and collector design reduce backpressure (drive pressure), improve turbo efficiency, and stabilize temperatures under load.

1. Efficient flow: Smooth internal paths reduce turbulence and backpressure for better throttle response and lower EGT.
2. Heat expansion control: Three-piece performance designs allow controlled movement during thermal cycling, helping prevent cracks and gasket leaks.
3. Customization: Upgrading supports stronger mid-range torque, quicker spool, and consistent towing performance.

How to choose the right 5.9 Cummins manifold

• Keeping the stock turbo: Choose a stock-replacement T3 pattern for direct fit and improved durability.
• Upgrading the turbo: A T4/T4i performance manifold provides more flow and stable boost control for larger S300/S400 frames.
• Towing & heat management: Prioritize thicker castings, flat-machined flanges, and pre-tapped ports for EGT/drive pressure monitoring.

Fitment

Designed for 5.9L Cummins in Ram 2500/3500 (1998–2007). Verify head flange pattern, turbo inlet (T3/T4/T4i), wastegate style, and downpipe alignment per the product page for your model year.

When to replace your manifold

• Ticking/hissing on cold start that lessens warm (leak or crack at divider walls).
• Soot trails near flange edges or gasket surfaces.
• Slower spool or higher EGT after load with no other changes.
• Warped flanges or recurring gasket failures after torque checks.

Install & maintenance tips

• Use new gaskets and quality hardware; follow factory torque sequence in stages on a cold engine.
• Apply high-temp anti-seize to studs/nuts; re-torque after initial heat cycles if specified.
• Confirm turbo face flatness, downpipe alignment, and no pre-turbine leaks.
• Add EGT (and drive pressure, if equipped) monitoring for towing or performance use.

Planning related upgrades? See S300 Single Turbos and Add-A-Turbo Kits. For 6.7L applications, visit the 6.7 Cummins Manifolds page.

Frequently asked questions

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