1. Year and Model of the Engine: 350 Chevy small blocks were produced for many years with variations in block casting and accessory placement. The year and model significantly impact the pump's mounting style and dimensions. Early and later 350s might have different water pump bolt patterns or inlet/outlet configurations.
2. Type of Cooling System: Consider whether you have a standard cooling system or a performance setup (e.g., high-performance radiator, electric fans, etc.). A high-performance system may require a higher-flow water pump.
3. Application: Is this for a street car, a race car, or off-road vehicle? This determines the level of durability and performance needed. Race cars might demand a pump with higher flow rates and different materials.
4. Water Pump Style:
* Standard Rotation: Most common type.
* Reverse Rotation: Used in some applications to improve belt routing or address clearance issues.
* High-Flow: Increased flow rate for performance applications. Often used with performance radiators and larger cooling systems.
5. Materials:
* Cast Iron: Durable and common, but heavier.
* Aluminum: Lighter weight and better heat dissipation, but potentially more susceptible to corrosion.
How to Find the Right Pump:
1. Identify your engine: Look for casting numbers on the engine block to determine the exact year and model. This is crucial.
2. Check existing water pump: If you still have the old pump, note the manufacturer, part number, and any markings on it. This can be a good starting point when searching for a replacement.
3. Consult a parts catalog: Use online parts catalogs (e.g., Summit Racing, Jegs, Napa Online) or a physical catalog from a parts store. Input your engine's year and model to find compatible water pumps. Pay close attention to specifications such as bolt pattern, inlet/outlet size and location, and rotation.
4. Check dimensions: Ensure the pump's dimensions are compatible with your engine and accessories. Make sure it clears the timing cover, fan, and other components.
5. Consider performance needs: If you're building a high-performance engine, look for a high-flow water pump designed for that application.
In short: Don't just order a "350 Chevy water pump." Be specific about the engine's year and model. Using online parts catalogs and providing the correct year, model, and any other relevant information (like whether it's a small block or big block) will yield the best results. If uncertain, contact a parts store or a specialist in classic Chevy engines for assistance.
