Choosing the Right Spark Plugs for Your 1955-1960 Buick Special
Keep your classic Nailhead V8 running smoothly with the correct new aftermarket spark plugs.
- Modern aftermarket spark plugs from brands like Champion, NGK, and Denso are reliable replacements for the original AC Delco plugs.
- The correct spark plug gap is crucial for performance; set it between .030" and .035".
- There are no specific recalls or TSBs for spark plugs on this vehicle; most ignition issues stem from other aging components.
- Replacing spark plugs is a simple, low-cost maintenance task that you can do yourself to improve engine performance and reliability.
Signs of Failing Spark Plugs in Your Buick
Worn or fouled spark plugs can cause a number of noticeable issues in your 1955-1960 Buick Special. Because these cars do not have modern computer systems, paying attention to how the engine feels and sounds is key. Common symptoms include a rough idle, engine hesitation or misfiring, reduced power, and a decrease in fuel economy. In some cases, the engine may become hard to start. Visual inspection is also important; plugs that are black with soot, wet with oil, or have obviously worn or damaged electrodes need to be replaced.
Choosing Your Aftermarket Spark Plugs
For a vintage vehicle like the 1955-1960 Buick Special, the concept of "OEM vs. Aftermarket" is different than for a modern car. The original AC Delco plugs from the 1950s are no longer made. Today, high-quality aftermarket brands like Champion, NGK, and Denso offer excellent replacements that meet or exceed the original specifications. In fact, many classic car owners prefer modern plugs from these brands for their reliability and performance.
The original plug specified was often an AC 44 or similar variant, with the AC R45S becoming a common service replacement. This cross-references to several modern plugs. The most important factors are choosing the correct heat range, thread size (14mm), reach (3/8 inch), and using a gasket seat.
Aftermarket Brand Tiers
| Tier | Brands | Characteristics & Vehicle-Specific Notes |
|---|---|---|
| Good (Standard Replacement) | Champion, Autolite, AC Delco Conventional | These are basic, reliable copper-core plugs that work very well in the Nailhead V8. They are affordable and perform just like the originals. Many owners use standard AC Delco or Autolite plugs with great success. They require more frequent changes than premium plugs but offer excellent value. |
| Better (Upgraded Performance) | NGK V-Power, Denso U-Groove | NGK's V-Power plugs feature a V-cut in the center electrode which can improve ignitability for quicker starts and a smoother idle. These are a popular and highly-regarded upgrade among classic car enthusiasts for their reliability and consistent performance. |
| Best (Premium/Long Life) | NGK Iridium IX, Platinum Plugs | Iridium and platinum plugs are designed for longevity and performance enthusiasts. They have a very high melting point and resist wear, maintaining their gap for much longer. While effective, the benefit in a stock, carbureted engine like the Nailhead may not be as noticeable as in a modern high-energy ignition system. They are a good choice if you want the longest possible service interval. |
A Note on Spark Plug Non-Foulers
You may see "non-fouler" adapters sold for these vehicles. These devices are used to pull the spark plug slightly out of the combustion chamber to prevent it from being fouled by oil. This is a temporary fix for an engine that is burning oil due to worn piston rings or valve seals. It does not solve the root problem.
Known Issues, Recalls, or Service Bulletins
There are no active recalls or technical service bulletins (TSBs) from the NHTSA regarding spark plugs for the 1955-1960 Buick Special. Ignition problems on these cars are common due to age but are typically related to the distributor, points, condenser, coil, or wiring rather than a specific defect in the spark plugs themselves.
Frequently Asked Questions (FAQ)
What is the correct spark plug gap for my Buick Special?
The correct spark plug gap for a stock 1955-1960 Buick Special is between .030" and .035". Always double-check the gap on new plugs with a wire-style feeler gauge before installation.
Should I use resistor or non-resistor plugs?
Resistor plugs (often designated with an "R" in the part number, like AC Delco R45S) were introduced to reduce radio frequency interference (RFI) that causes static in the AM radio. For a stock car with a radio, resistor plugs are recommended. They will not negatively impact performance.
How tight should I install the spark plugs?
The factory specification is 22-28 ft. lbs. of torque. Make sure the plug and cylinder head surfaces are clean and that the gasket is in good condition. If you don't have a torque wrench, a common method is to screw the plug in by hand until it seats, then tighten it an additional 1/4 turn with a wrench. Do not overtighten.
Do I need special tools to change the spark plugs?
You will need a 13/16" spark plug socket, a socket wrench, and an extension. A spark plug gap gauge is also essential to ensure the plugs are gapped correctly before installation. A torque wrench is highly recommended for proper installation.
Technical Specifications
OEM Part Numbers: AC 44 AC 44-5 AC 44S AC R45S
Thread Size: 14mm, Thread Reach: 3/8" (9.5mm), Seat: Gasket, Hex Size: 13/16", Recommended Gap: .030" - .035"
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.