How to check and replace spark plugs on a 1967 Shelby GT500?

Experiencing issues with your 1967 Shelby GT500 can often be traced back to the spark plugs. Misfires, poor fuel economy, and difficulty starting the engine are common symptoms indicating that it's time to check and, if necessary, replace the spark plugs. Here is how to resolve this issue:

Step 1: Gather Your Tools and Materials

First, ensure you have all necessary tools and materials at hand:

• Spark plug socket
• Ratchet wrench
• Extension bar (optional but useful)
• Spark plug gap tool
• Anti-seize lubricant (optional)
• New spark plugs (consult your vehicle owner’s manual for the correct type)

Step 2: Locate and Remove the Engine Cover

Pop the hood and locate the engine cover if your Shelby GT500 has one. The engine cover is typically in the center of the engine bay and covers the entire engine block. It usually attaches with bolts or clips. Remove it to gain clear access to the spark plugs.

Step 3: Identify the Spark Plug Wires

The spark plugs on your Shelby GT500 are located along the sides of the engine block. You'll see thick, rubber-covered wires (spark plug wires) plugged into the engine block—they connect to the individual spark plugs. Trace these wires to find the spark plug locations.

Step 4: Remove the Spark Plug Wires

Carefully remove one spark plug wire at a time to avoid mixing them up. Grasp the boot at the end of the wire (not the wire itself) and gently twist and pull to release it from the plug. Avoid using excessive force to prevent damaging the wire.

Step 5: Remove the Spark Plugs

Insert the spark plug socket onto the ratchet wrench and carefully fit it over the exposed spark plug. Turn the ratchet counterclockwise to unscrew and remove the spark plug. If space is tight, an extension bar can provide better leverage and reach.

Step 6: Inspect and Gap the New Spark Plugs

Compare the old spark plugs to your new ones to ensure they match. Use a spark plug gap tool to check the gap on the new spark plugs. Adjust the gap as needed according to the specifications outlined in your vehicle owner's manual.

Step 7: Install the New Spark Plugs

If using anti-seize lubricant, apply a small amount to the threads of the new spark plugs. Carefully thread each new spark plug into the spark plug hole by hand to avoid cross-threading. Once seated, use the ratchet to tighten them. Be cautious not to over-tighten as this can damage the spark plug.

Step 8: Reattach the Spark Plug Wires

Reattach each spark plug wire by pushing the boot firmly over the new spark plug until it clicks into place. Ensure each wire connects to the correct plug to maintain proper firing order.

Step 9: Replace the Engine Cover

If you removed an engine cover, reattach it by securing the bolts or clips. Ensure everything is snug and correctly placed.

Step 10: Test the Engine

With everything back in place, start your Shelby GT500 and listen for a smooth, consistent engine idle. This indicates successful installation of the new spark plugs. If the engine runs rough or exhibits misfires, double-check the spark plug gaps and wire connections.

By following these steps, you should be able to check and replace the spark plugs on your 1967 Shelby GT500, ensuring optimal engine performance and reliability.