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5.9 12V Cummins | 1988 – 1993

First Gen 5.9 12-Valve Cummins Parts (1989–1993)

Keep your 1st Gen working hard with upgrades that improve spool, airflow, and towing power while protecting reliability. Diesel Power Source designs clean-fit turbos and exhaust manifolds for 1989–1993 Dodge Ram 5.9L 12-valve Cummins.

This page highlights first-gen specific parts and fit notes. If you need 24-valve or common-rail components, or universal turbo categories, use the links at the bottom. Detailed specs and year-specific contents are listed on each product page.

Why upgrade your 1989–1993 12V Cummins

  • Quicker spool and response: Flow-optimized manifolds and right-sized turbos help the VE-rotary pump builds pull sooner.
  • Lower EGT on grades: Better exhaust flow reduces drive pressure and heat when towing.
  • Durability: Thick-wall castings and flat-machined flanges resist warping and leaks through repeated heat cycles.
  • Clean fitment: Parts are modeled around first-gen bay clearances for service access and repeatable installs.

How to choose parts for a 1st Gen 12V

  • Towing and daily use: Choose a stock-replacement manifold and a quick-spooling turbo. Monitor EGT on first towing runs.
  • Street performance: Step to a slightly larger compressor with the correct turbine housing to hold speed on grades without excessive lag.
  • Higher fuel builds: Plan airflow headroom with appropriate turbine A/R, quality intercooling, and a converter or gearing that matches the goal.

Fitment checklist for 1989–1993

  • Confirm T3 vs T4 turbo flange on the manifold you select.
  • Verify downpipe route, intercooler path, and clearance at steering shaft and A/C lines.
  • Plan new gaskets, hardware, heat shielding, and sensor ports if you log EGT or drive pressure.

Install and first drive notes

  • Use new gaskets and quality hardware. Torque in sequence on a cold engine.
  • Pressure test the charge-air system before first start. Check for any pre-turbine leaks.
  • Monitor boost and EGT on shakedown. Re-check fasteners after heat cycles if specified.

Shopping related categories? 5.9 Cummins Manifolds (12V, 24V, common-rail) | S300 Single Turbos | S400 Single Turbos | Add-A-Turbo Kits. For later engines, see 6.7 Cummins Manifolds.

 

1988–1993 12-Valve Cummins Performance FAQs

Diesel Power Source offers turbochargers, exhaust manifolds, turbo upgrade kits, airflow components, and supporting hardware designed specifically for early 12V Cummins applications. These parts are built to improve power, drivability, and durability while maintaining the mechanical simplicity of the engine.

Upgrading the turbo on a 12V Cummins can reduce turbo lag, improve throttle response, increase horsepower and torque, and help manage exhaust gas temperatures. Many owners upgrade to support towing, heavier loads, or future fuel system modifications.

The right upgrade depends on your goals, whether that’s towing, daily driving, reliability, or increased horsepower. Diesel Power Source offers expert support to help match the correct turbo or manifold to your setup and future plans.

This category covers Dodge Ram trucks equipped with the 5.9L 12-valve Cummins diesel engine from 1988 to early 1993, commonly referred to as first-generation Cummins trucks.

Yes. Products in this category are selected and designed to support first-generation Dodge Cummins platforms, accounting for early exhaust layouts, mechanical fueling systems, and factory mounting configurations.

Diesel Power Source specializes in Cummins-focused performance solutions, offering proven designs, in-house product knowledge, and technical support tailored to older 12-valve platforms that are still widely used today.

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