A Diesel Power Source® 6.7 Cummins exhaust manifold replaces the factory one-piece manifold with a multi-piece design cast from High Silicon Molybdenum Ductile iron (HSMD). The sections are hydraulically pressed together, so the manifold can expand and contract with heat instead of cracking, warping, or shrinking. DPS builds two factory-replacement manifolds, the T4i for 2007.5-2018 trucks and the 5G for 2019-2024 trucks, plus two T4 manifolds for builds running an aftermarket T4 turbo. Every manifold is CFD tested and pressure-tested before it ships.
About 72% More Flow
T4i manifold compared to the factory manifold, CFD tested
Over 75% on 5th Gen
5G manifold compared to the factory manifold, CFD tested
Multi-Piece Press Fit
Expansion joints absorb thermal stress instead of the casting
Emissions Compatible
T4i and 5G manifolds work with factory emissions equipment
Why the Factory 6.7 Cummins Manifold Fails, and What DPS Changes
One-Piece Castings Crack and Shrink
The Cummins inline six is a long engine, and repeated heat cycles put heavy stress on a one-piece manifold. Over time it cracks, warps, and shrinks. By 100,000 miles or more, the shrinkage can side-load the bolts so heavily that the manifold has to be cut to get it off the head.
Multi-Piece Press-Fit Joints
DPS manifold sections are hydraulically pressed together on a precision jig, with no gasket or seal ring at the joint. Each section expands and contracts on its own, and the joint tightens as the manifold heats up.
HSMD Iron, Not Stainless
HSMD is rated approximately 200°F higher than traditional cast iron. Stainless steel expands and contracts about twice as much as ductile iron, which breaks bolts and destroys gaskets on a long six-cylinder engine. Ductile iron holds stable clamping pressure through heat cycles.
CFD-Tested Runners
CFD testing sets runner sizing, flow balance, and exhaust velocity. Lower drive pressure lets the turbo reach boost sooner. Pickup manifolds typically lower EGTs by approximately 25-75°F, most noticeably under sustained load. The turbo is the primary EGT bottleneck, so results depend on the whole system.
Fitment
- T4i manifold: 2007.5-2018 Ram 2500/3500 6.7L Cummins
- 5G manifold: 2019-2024 Ram 2500/3500 6.7L Cummins
- T4 manifolds: aftermarket T4-flange turbos only
- Cab and chassis (3500/4500/5500): some trucks have one EGR port and DPS manifolds have two. Photos of the factory manifold are required before purchase.
- Tell DPS your year, your turbo (factory or aftermarket), and the flange if it is aftermarket.
Install Notes
- Manifolds ship fully assembled, aligned, and pressure-tested. No assembly is required.
- Always use new gaskets, and replace stretched or corroded studs and nuts.
- DPS does not recommend anti-seize on manifold hardware.
- Torque is approximately 40 ft-lbs on the 6.7L. Confirm the value and sequence in the install instructions for your manifold.
- With standard bolts, re-torque after 50-100 miles at operating temperature. Spin Lock serrated hardware typically does not need a re-torque.
- Warranty under the Diesel Power Source® PMA: manifolds 1 year. Registration within 14 days of purchase is required.
Hardware and Gasket Kits
Related categories: 5.9 Cummins Manifolds | ISX15 / X15 Exhaust Manifolds | All Exhaust Manifolds | HE300VG VGT Turbos | 6.7 Cummins Parts. Questions on fitment? Call 801-930-8404 or email sales@dieselpowersource.com. Free shipping on orders over $350.
Cummins is a registered trademark of Cummins Inc. Diesel Power Source® is not affiliated with Cummins Inc.
