Water Pump LS1 Long GEN III & IV

The STEWART Water Pump LS1 Long for GM LS-Series Generation III and IV engines delivers high-volume cooling capacity in a compact, aluminum construction designed for serious engine builders and performance enthusiasts. This mechanical water pump combines proven Stewart engineering with the flow characteristics needed for upgraded cooling systems in modern LS platform swaps, turbocharged builds, and high-horsepower street and race applications.

Engineered specifically for LS-series compatibility, this long-style pump is sized to work seamlessly with both Gen III and Gen IV block variants, eliminating fitment guesswork. The aluminum construction reduces parasitic weight while maintaining structural rigidity under sustained high-RPM operation. High-volume flow ratings ensure adequate coolant circulation in applications where factory cooling capacity falls short—critical for turbocharged setups, track-duty engines, or any platform running elevated boost pressures or prolonged full-throttle conditions. The pump's natural aluminum finish pairs cleanly with most engine bay aesthetics.

This pump serves engine builders, performance shops, and DIY enthusiasts undertaking LS engine conversions or upgrades where OEM cooling systems require augmentation. Real-world users installing this pump typically pair it with upgraded radiators, expanded coolant capacity, and precision thermostatic control to maximize engine longevity under demanding conditions. Whether supporting a street LS swap, autocross competitor, or road-course platform, the STEWART design provides the flow rate and durability expected in professional and serious amateur builds.