Mopar S/D 2.250 Intake Valves

The Manley Mopar S/D 2.250 Intake Valves (MPN 11904-8) are severe-duty stainless steel intake valves engineered for high-performance Mopar 426 Hemi engines. This set of eight valves features a 2.250-inch head diameter and 0.309-inch valve stem, delivering the precision engineering required for extreme duty applications where standard components fall short. Stainless steel construction resists thermal stress and corrosion inherent in severe-duty engine operation, making these valves the choice for builders demanding reliability under sustained high-load conditions.

Each valve measures 5.424 inches in overall length, precisely dimensioned to maintain proper seating and flow characteristics in Hemi cylinder heads. The 2.250-inch intake diameter optimizes air charge for the displacement and combustion efficiency of the 426 platform, while the 0.309-inch stem diameter matches OEM bore specifications for accurate valve guide fitment. Stainless construction elevates durability over cast iron alternatives, particularly critical in severe-duty scenarios involving sustained RPM, high boost pressure, or extended heat cycling where material fatigue becomes a limiting factor.

This set is built for engine builders, performance shops, and operators restoring or upgrading 426 Hemi powerplants for drag racing, marine propulsion, or heavy-duty industrial applications. Severe-duty valve sets are installed during comprehensive engine rebuilds where OEM components cannot meet the thermal and mechanical demands of the application. Manley's reputation in high-performance valve manufacturing reflects decades of competition and field validation, ensuring these intake valves perform consistently across thousands of heat cycles.

The 426 Hemi platform remains one of the most sought-after big-displacement engines for vintage and modern performance builds. Intake valve quality directly influences cylinder head breathing, fuel economy, emissions compliance, and longevity under load. Upgrading to severe-duty stainless valves represents a critical investment in engine reliability, especially when cylinder heads are freshly ported or modified for increased airflow.