This is a Rebuilt Water Pump Assembly for all 1937-1940 Chevrolet cars & trucks. It is a replacement pump for 1937 & 1938 bushing type water pumps. This water pump has sealed bearings. Replaces GM# 838903 & 598308. This is a rebuilding service and we need your original SEALED BEARING pump to rebuild. BUSHING TYPE PUMPS ARE NOT ACCEPTABLE AS A CORE FOR THIS PUMP. If no rebuildable core is provided, there will be a core charge of $150.00 if stock is available.