Autolite 303 Spark Plug

Reliable Ignition Performance for Chevrolet, GMC, and Pontiac Vehicles

The Autolite Copper Resistor Spark Plug 303 is engineered to deliver consistent ignition performance for select Chevrolet, GMC, and Pontiac models. Designed with durable materials and precise specifications, this spark plug supports efficient combustion and engine reliability.

• Resistance: 5000 ohms for effective electrical noise suppression
• Center electrode core made of copper with a nickel tip for optimal conductivity and durability
• Tapered ground electrode tip constructed from nickel for improved spark exposure
• Removable nut electrical terminal type for easy installation and maintenance
• Ceramic short insulator for enhanced heat dissipation and insulation
• Flat seat type with a 14.0 mm thread diameter and 9.5 mm reach
• Pre-gap size of 0.034 inches (0.90 mm) for precise spark gap
• Hex size options of 13/16" (21 mm) for compatibility with standard tools

About the Autolite Copper Resistor Spark Plug Line

The Copper Resistor Spark Plug line from Autolite is designed to provide reliable ignition with built-in resistance to reduce radio frequency interference. This line features copper core electrodes for improved heat transfer and consistent spark delivery, making it suitable for a range of secondary ignition applications. The resistor type spark plugs help maintain engine performance while protecting sensitive electronic components.

Technical Details and Compatibility

This spark plug features a single nickel ground electrode with a tapered tip and a standard center electrode design. The ceramic short insulator enhances durability and heat management. With a flat seat and a thread diameter of 14.0 mm, the Autolite 303 spark plug fits select Chevrolet, GMC, and Pontiac vehicles including the Bel Air, Blazer, C10 Suburban, C20 Suburban, Corvette, El Camino, Jimmy, K10 Suburban, K20 Suburban, Laurentian, and Parisienne models.

Common Applications and Problem Solving

• Restores proper ignition in vehicles experiencing misfires or rough idling
• Reduces electrical interference affecting radio and onboard electronics
• Improves fuel efficiency by ensuring consistent spark delivery
• Prevents fouling and electrode wear in older ignition systems
• Supports stable engine performance under various driving conditions

Installation Notes and Tips

Before installation, verify the spark plug gap is set to the specified 0.034 inches (0.90 mm). Use a torque wrench to tighten the spark plug to manufacturer-recommended specifications to avoid damage to the flat seat or threads. The removable nut terminal allows for easier connection to ignition wires. Inspect the ignition system components for wear or damage during replacement to ensure optimal performance.

Quality Assurance and Warranty

Autolite spark plugs are manufactured to meet industry standards for durability and performance. The Copper Resistor Spark Plug 303 undergoes rigorous quality control to ensure consistent resistance and electrode integrity. While specific warranty details may vary, Autolite products typically come with a limited warranty against manufacturing defects.