1. Look for the List Number:
* Primary Identification: This is the most reliable method. The list number is usually stamped or cast into the carburetor body itself. It's a series of numbers (e.g., 4160, 4150, 600 CFM, etc.) often located on the primary body, near the air horn or throttle linkage. This number will directly lead you to the specific model in Holley's documentation or online databases.
2. Examine the Physical Characteristics:
* Size and Shape: The overall size and shape (especially the air horn) can offer clues. Different models have different airflow capacities (CFM), resulting in varying sizes.
* Number of Barrels: Count the number of barrels (venturi). Common ones are 2-barrel (smaller engines) and 4-barrel (larger engines).
* Type of Choke: The choke mechanism (manual, automatic, electric) is another differentiating factor.
* Fuel Bowl Configuration: The shape and features of the fuel bowls can be model-specific.
* Floats: While not always definitive, the type and shape of the floats can provide a hint.
* Secondary Metering System: The design and type of secondary metering system (e.g., vacuum secondary, mechanical secondary) will help narrow down the possibilities.
3. Utilize Online Resources:
* Holley's Website: The official Holley website is the best resource. Their parts catalog and technical documentation can help you identify the model based on its list number or physical characteristics.
* Online Forums and Communities: Forums dedicated to carburetors and specific engines (e.g., forums for classic car enthusiasts) often have knowledgeable members who can help with identification. Post clear pictures of your carburetor from various angles.
* Image Search: Try searching online image databases (like Google Images or Bing Images) using descriptive terms like "Holley 2-barrel carburetor," "Holley 4150," etc. Compare your carburetor's physical features to images of known models.
Important Considerations:
* Modified Carburetors: If the carburetor has been modified or rebuilt, identifying the original model might be difficult or impossible.
* Missing Parts: Missing parts can make identification harder.
* Clear Images: If you're relying on online help, provide clear, well-lit photos from multiple angles. Close-ups of the list number and other identifying features are crucial.
By systematically checking these elements and utilizing online resources, you'll significantly improve your chances of identifying the exact model of your Holley carburetor.
