First Gen Cummins Exhaust Manifold | 12 Valve Cummins Performance Upgrade
Fits 1988–1993 Dodge Ram 5.9L First Gen Cummins
CARB Exempt – Legal for Installation and Street Use in California
The DPS First Gen Cummins Exhaust Manifold is a high-performance, direct bolt-on replacement for 1988–1993 5.9L 12V Cummins engines. Designed specifically for the 1st Gen rectangular port head, this manifold flows significantly better than stock, reduces rear-cylinder EGTs, and provides maximum durability with 3-piece expansion joints.
Top Features & Benefits:
- Flows 23% more than OEM 1st Gen Cummins manifold
- CFD tested and balanced for smooth exhaust velocity and better turbo spool
- Includes 6 exhaust manifold gaskets
- Three drilled and tapped ports for pyrometer and pressure fittings—including bottom port
- Manufactured from nickel-laced ductile iron for extreme heat resistance
- Black high-temp coating for corrosion protection
- Ships pressed together and ready to install
- Direct replacement for OEM parts: 3911349
Why Choose DPS Over Stainless Manifolds?
Single-piece stainless manifolds expand and contract up to 2x more than our ductile iron manifold. That extra movement stresses your head, gaskets, and bolts—leading to leaks or failures. The DPS 3-piece design allows natural thermal flexing without damage.
Purpose-Built Mold for 12V Rectangular Ports
Most competitors machine their 24V round-port castings to fit 12V heads. This creates smaller, restricted ports and poor airflow transitions. The DPS First Gen manifold uses a dedicated rectangular port mold—engineered specifically for 12V flow performance. It’s more expensive to produce, but gives you better power, smoother EGTs, and optimal fitment.
OEM Replacement Part Numbers:
- 3911349
**When upgrading to the Spin Lock Bolt or Multi-Layer Gasket Kit, please note that these are upgraded components. The standard bolts and gaskets will not be included with the upgrade option.
4 Reviews
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DPS X 98 12V s362 turbo215 Pump
This Manifold has done what is says. Turned up 12V 362 turbo injectors and AFC mods on a 5 Speed. Lowered EGT by 75 degrees and spools at around 1550 Rpms about 200 Rpms faster than the stock Manifold. Easy to install Nice coating and welded between flanges all in a 3 piece. Sure will last for a long time. Truck runs smoother and doesn't feel laggy at all had to remove some pre boost to tone her down a bit. Thanks DPS just what I needed .
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Perfect!
sounds like new truck at 305k...mine shrank badly on ends, does make my 66mm turbo sing 2-300 rpms earlier and the top end it loud n pulls hard but also has light pedal power too
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12v Manifold
Great manifold and even better price compared to others costing more.
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On time
Shipping was sooner than expected and product is exactly as advertised
