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6.7 Cummins Manifolds

6.7 Cummins Exhaust Manifolds | 2007.5 to 2024 Ram 2500/3500

High-Flow Multi-Piece Ductile Iron Manifolds for 4th Gen and 5th Gen Ram

Diesel Power Source® 6.7 Cummins exhaust manifolds flow up to 72% more than the factory casting, eliminate the cracking and warping that plague OEM manifolds, and are fully emissions compatible with all factory systems.

The factory 6.7 Cummins exhaust manifold is a thin, single-piece casting designed for cost and packaging rather than performance or longevity. Under the sustained heat and thermal cycling that towing and daily driving produce, the factory manifold cracks at the divider walls, warps at the flanges, and eventually creates exhaust leaks that reduce turbo efficiency and raise EGTs. DPS 6.7 manifolds use a multi-piece expansion joint design cast from High Silicon Molybdenum Ductile Iron (HSMD) with hydraulically pressed joints that get tighter as temperature increases rather than degrading over time.

Up to 72% More Flow

CFD-tested T4i manifold dramatically outflows the factory casting

Multi-Piece Design

Expansion joints prevent cracking and warping from thermal cycling

Emissions Compatible

All 6.7 manifolds work with factory EGR, DPF, and emissions systems

HSMD Ductile Iron

High Silicon Molybdenum Ductile Iron for maximum thermal durability

6.7 Cummins Manifolds by Generation

  • T4i Manifold for 2007.5 to 2018 (4th Gen) — 2-piece expansion joint design. 72% more flow than factory (CFD tested). T4i flange fits factory turbo location. Two EGR ports. Emissions compatible. Does NOT fit Cab and Chassis models with single EGR port.
  • 5G Manifold for 2019 to 2024 (5th Gen) — 2-piece expansion joint design. Over 62% more flow than factory (CFD tested). Unique lower-mount angled turbo flange. Emissions compatible.
  • T4 2G Swap Manifold for 2007.5 to 2018 — 2-piece, center mount. NOT OEM replacement. For aftermarket T4-flange turbo builds and 2nd gen swap configurations. Has EGR ports.

Which 6.7 Cummins Manifold Do I Need?

  • Keeping the factory turbo (T4i flange, 2007.5 to 2018): Choose the T4i manifold. Direct bolt-on replacement with 72% more flow. Emissions compatible.
  • Keeping the factory turbo (5th gen, 2019 to 2024): Choose the 5G manifold. Direct bolt-on replacement with over 62% more flow. Emissions compatible.
  • Running an aftermarket T4 turbo or 2G swap: Choose the T4 2G Swap manifold. NOT OEM. For aftermarket turbo builds only.
  • Replacing turbo and manifold together: Consider the HE300VG Turbo and Manifold Package (2007.5 to 2018) or the 5th Gen Turbo and Manifold Kit (2019 to 2024). One job, one labor cost, both failure points solved.

Why the Factory 6.7 Manifold Fails

  • Thin casting: Factory manifold is designed for cost, not durability under sustained load
  • Single-piece design: Cannot absorb thermal expansion without cracking
  • Divider wall cracking: Internal walls between cylinders crack under repeated heat cycles
  • Flange warping: Over time, flanges warp enough to cause gasket failures and exhaust leaks
  • Manifold shrinkage: By 100,000+ miles, some factory manifolds have shrunk so severely they cannot be removed without cutting

Construction and Materials

  • Material: High Silicon Molybdenum Ductile Iron (HSMD) on every manifold
  • Design: 2-piece expansion joint with hydraulically pressed joints (no gasket at expansion joints)
  • Coating: Black high-temperature ceramic (rated to 1,400°F)
  • CFD tested: Every manifold designed and validated with Computational Fluid Dynamics
  • Pressure tested: 100% of manifolds pressure-tested before shipping
  • Pre-tapped ports: Pyrometer and pressure sensor ports ready for installation

Cab and Chassis Compatibility

DPS does NOT have a dedicated Cab and Chassis manifold for the 6.7 Cummins. Some Cab and Chassis trucks (Ram 3500/4500/5500) have only one EGR port, while DPS manifolds have two. If your Cab and Chassis truck has both EGR ports, compatibility may be possible on a case-by-case basis. Cab and Chassis customers must send photos of their factory manifold to DPS before purchase. Contact us at 801-930-8404 or sales@dieselpowersource.com.

Installation Notes

  • Always use new gaskets. Do not reuse OEM gaskets.
  • Replace stretched or corroded studs and nuts. DPS Spin Lock kits are recommended.
  • Anti-seize is NOT required or recommended by DPS. Customer discretion only.
  • Follow cross/circular torque pattern on a cold engine.
  • With Spin Lock serrated bolts, re-torquing is typically NOT required.
  • With standard non-serrated bolts, hot torque recommended after 50 to 100 miles. Use gloves.
  • Professional installation is NOT required for warranty coverage.

Related categories: 5.9 Cummins Manifolds | ISX15 Manifolds | Compound Turbo Kits | Add-a-Turbo Kits | 3rd Gen Swap Kits

6.7L Cummins Exhaust Manifold FAQs

A high-flow 6.7L Cummins exhaust manifold improves exhaust distribution to the turbo, reduces drive pressure, and helps control EGTs under load. Compared to the factory manifold, a performance manifold supports faster spool, steadier boost, and improved efficiency, especially during towing and long pulls.

A stock-replacement manifold is ideal for trucks keeping the factory turbo or VGT and wanting better reliability and lower backpressure with a direct bolt-on install. A T4 manifold is designed for trucks upgrading to larger frame turbos or planning future power increases. The right choice depends on turbo selection, towing needs, and long-term build goals.

Yes. When installed correctly, a performance manifold can reduce exhaust restriction and stabilize turbo operation, which helps lower EGTs and improve drivability even with factory emissions equipment in place. Many towing trucks see cooler temperatures and more consistent boost on long grades without requiring tuning for the manifold alone.

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