What year did Dodge switch to the 24 valve?
Dodge switched to the 24-valve Cummins in the 1994 model year Ram pickups.
The move marked a major shift from the older 12-valve design and set the course for Dodge’s heavy-duty diesel lineup for years to come. This article lays out the timeline, the reasons behind the change, and how the 24-valve architecture influenced Dodge's diesel program from the 1990s onward.
Year of the switch
The pivotal moment came with the 1994 model year, when Dodge introduced the 5.9L Cummins Turbo Diesel in Ram 2500/3500 equipped with a 24-valve cylinder head.
- 1994 model year: Dodge Ram 2500/3500 launches with the 5.9L Cummins Turbo Diesel featuring a 24-valve head, replacing the earlier 12-valve configuration.
That year marks the turning point in Dodge’s diesel evolution, establishing a 24-valve foundation that would underpin the Ram heavy‑duty lineup for years to come.
Impact and design implications
Adopting a 24-valve configuration affected performance, durability and maintenance expectations for Dodge's diesel pickups.
- Increased airflow and combustion efficiency from four valves per cylinder (in this inline-6 layout) enabled higher torque peaks and better high-load performance.
- Enhanced injector control and durability laid groundwork for later electronic fuel systems and emissions-compliant designs.
- Improved reliability under heavy-duty use helped cement Dodge’s reputation for diesel capability in the HD market.
These design shifts positioned Ram HD trucks to compete effectively in the diesel market throughout the late 1990s and into the 2000s.
Current context and legacy
Today, the 24-valve architecture remains a hallmark of Ram’s diesel lineup. A major evolution came with the 6.7L Cummins Turbo Diesel, introduced for the 2007 model year, which continued the 24-valve tradition with modern emissions controls and power management.
- 2007 model year: Introduction of the 6.7L Cummins Turbo Diesel for Ram Heavy Duty trucks, continuing the 24-valve lineage.
- Ongoing use of 24-valve architecture across generations, adapted for emissions and efficiency improvements.
The 24-valve lineage has persisted as a core element of Dodge’s diesel performance, reflecting decades of refinement in durability, power, and efficiency.
Summary
Dodge’s switch to the 24-valve Cummins occurred with the 1994 model year Ram pickups, establishing a durable 24-valve diesel tradition that evolved through the 2000s and continues today with modern Ram diesels such as the 6.7L Cummins.
