* Automatic or Manual Transmission: The transmission's location impacts header clearance.
* Power Steering: The power steering pump and its placement can affect header routing.
* Air Conditioning: The AC compressor can also influence header clearance.
* Exhaust System Setup: Dual exhaust, single exhaust, and the intended routing of the pipes.
Because of these variations, there isn't one single "fits all" header. You'll likely need to search for headers specifically advertised for a 1967 Thunderbird with a 390 engine, and even then, carefully check the manufacturer's specifications for compatibility with your particular options (auto/manual trans, PS, AC).
Where to look:
* Classic Thunderbird Parts Suppliers: Websites and catalogs specializing in classic Thunderbird parts are your best bet. They will often list compatibility information.
* Header Manufacturers: Look at major header manufacturers (e.g., Hooker, Hedman, Doug Thorley, etc.) and check their application guides or contact their customer service.
* Online Forums: Forums dedicated to classic Thunderbirds are a great resource. Post your specific details (engine, trans, options) to ask for recommendations from other owners.
Important Considerations:
* Fit is crucial: Headers are often not a perfect bolt-on. You might need some modification for optimal fit and clearance.
* Tube Diameter: Header tube diameter affects performance. Research what diameter is best for your intended use.
* Header Style: Consider long tube headers vs. shorty headers, based on your goals (performance vs. ease of installation).
Don't hesitate to contact multiple suppliers with the details of your car to ensure the best fit. Improperly fitting headers can cause problems with clearance and exhaust leaks.
