Intermediate Shaft Chevy 348-409

The MELLING Intermediate Shaft for Chevy 348-409 (MPN IS-55A) is a stock-length oil pump drive shaft engineered for GM W-series big-block engines. This steel component operates as the critical mechanical link between the crankshaft and oil pump, ensuring consistent oil circulation under the high-demand conditions of classic Chevy performance engines. The IS-55A maintains OEM specifications and tolerances, making it the correct replacement for original 348 and 409 cubic-inch installations.

At 0.37 lbs with compact dimensions (8.25 × 2.05 × 0.85 inches), this intermediate shaft is a precision-machined component designed to transmit rotational force with minimal deflection. The natural steel finish resists corrosion under normal operating conditions typical of period-correct restorations. Stock length geometry ensures compatibility with original oil pump housings and crankshaft configurations—critical for avoiding misalignment that could lead to pump wear or inadequate oil delivery at idle and cruise speeds.

This replacement is ideal for owners restoring or rebuilding 348/409 engines who require OEM-specification components. Whether addressing wear in a long-stored engine or completing a comprehensive bottom-end overhaul, the IS-55A ensures the oil pump operates at design specification. Chevy big-block enthusiasts and restoration specialists depend on verified Melling components to maintain original performance characteristics and engine longevity.

Melling has established credibility within the engine rebuild market for precision-machined pump and shaft components. The IS-55A carries OEM-equivalent design, making it a trusted choice for period-correct restorations where pump failure is not an option.