How to check and replace spark plugs on a 1970 Dodge Challenger R/T?

Content verified by Michael G.
July 18, 2025
Learn how to check and replace the spark plugs on your 1970 Dodge Challenger R/T with this simple, step-by-step guide. Keep your car running at its best with this easy tutorial.

Owning a classic 1970 Dodge Challenger R/T brings a sense of pride, but it also comes with the responsibility of maintaining its performance. A common issue that may arise is worn-out spark plugs, which can lead to engine misfires, poor fuel economy, and sluggish acceleration. Knowing how to check and replace spark plugs is essential to keep your Challenger running smoothly. Here is how to solve this issue.

Step 1: Gather Necessary Tools and Materials

Before you start, make sure you have the following tools and materials:

  • New spark plugs (check the owner's manual for specifications)
  • Spark plug socket
  • Ratchet wrench
  • Spark plug gap tool
  • Anti-seize compound (optional)
  • Torque wrench
  • Compressed air (optional)

Step 2: Locate the Spark Plugs

The spark plugs on the 1970 Dodge Challenger R/T are located on the side of the engine block. There are eight spark plugs, four on each side if you have the V8 engine. Identify the spark plug cables, which are thick, rubberized wires connected to the engine cylinder head.

Step 3: Remove the Spark Plug Covers

Carefully remove the spark plug wires by pulling on the boot, not the wire. Gently twist the boot to break the seal and pull it off. Exposing the spark plugs, you’ll find them nestled into the engine block.

Step 4: Clean the Area

Use compressed air to blow away any dirt or debris around the spark plug area. This prevents debris from falling into the cylinder when you remove the spark plugs.

Step 5: Remove the Spark Plugs

Attach the spark plug socket to the ratchet wrench and place it over the spark plug. Turn counterclockwise to loosen and remove each spark plug. Be gentle to avoid stripping the threads in the engine block.

Step 6: Inspect the Spark Plugs

Check each spark plug for wear and deposits. A worn-out spark plug will have a worn electrode and heavy deposits. Compare the condition to the images in your vehicle's service manual to determine if replacement is necessary.

Step 7: Gap the New Spark Plugs

Using a spark plug gap tool, measure and adjust the gap to the specifications mentioned in your owner's manual. Proper gapping ensures optimal performance and fuel efficiency.

Step 8: Install the New Spark Plugs

Apply a small amount of anti-seize compound to the threads of the new spark plugs (optional). Insert the new spark plug into the socket, ensuring it stays aligned, and carefully hand-tighten it into the cylinder head to avoid cross-threading. Once hand-tightened, use a torque wrench to apply the manufacturer-specified torque setting.

Step 9: Reattach the Spark Plug Wires

Reconnect the spark plug wires to the new spark plugs. Make sure you hear a click sound, indicating that the boots are securely in place.

Step 10: Test the Engine

Turn on the engine to ensure it runs smoothly. Listen for any misfires or irregular sounds. If the engine runs smoothly, your spark plug replacement was successful.

By following these steps, you can ensure that your 1970 Dodge Challenger R/T maintains its performance and reliability, enabling you to enjoy your classic car to the fullest.

Still Struggling? Sign Up to Ask a Car Expert and Get a Consultation—For Free!

Join Our Community & Get Instant Access to Expert-Verified Repair Guides

What our members say

Discover how AutoFame.com has empowered fellow car enthusiasts—from weekend DIY mechanics to seasoned collectors—to document, restore, and celebrate their automotive stories like never before.

Stars - Elements Webflow Library - BRIX Templates

"AutoFame.com took my collection’s documentation to the next level. Before, I had scattered notes and old photos in boxes—now everything’s organized and accessible in one place. The AI-driven narratives also helped me craft a fascinating story around my ‘67 Mustang’s history that I proudly share at shows!"

Mark R., Classic Car Collector

Member since Dec'24
Stars - Elements Webflow Library - BRIX Templates

"I’m not a professional mechanic, but I love working on my car. AutoFame.com’s step-by-step guides and community forums gave me the confidence to tackle issues on my own. Last month, I fixed a stubborn headlight alignment problem in minutes. It’s like having a trusted car expert on speed dial."

Martin K., Weekend DIY Mechanic

Member since Sep'24
Stars - Elements Webflow Library - BRIX Templates

"AutoFame.com’s AI-driven insights blew me away. It automatically pulled up detailed specs and historical data on my BMW M3, and even composed a compelling narrative for my show board. When I shared it at a local event, everyone wanted to know how I put it together. AutoFame.com made me look like a pro!"

Alex M., Performance Enthusiast

Member since Sep'24
Stars - Elements Webflow Library - BRIX Templates

"I’ve been restoring my grandfather’s old Chevy pickup, and AutoFame.com has been a lifesaver. The vast data access helped me confirm original specs, and the documentation tools ensure I never lose track of my progress. My project went from chaotic guesswork to a well-organized, enjoyable journey."

Clara J., Restoration Hobbyist

Member since Jun'24
Stars - Elements Webflow Library - BRIX Templates

"AutoFame.com isn’t just about data—it’s about community. I run a local car club, and we’ve started using their event listings and forums to keep everyone updated. Our members love how easy it is to share photos, ask questions, and discover new shows. It’s brought our club closer together and boosted our turnout!

Trevor S., Car Club Organizer

Member since Jan'24
Icon - Elements Webflow Library - BRIX Templates
Icon - Elements Webflow Library - BRIX Templates

Classic cars have appreciated 185%

That's just over the last decade according to the night Franks Luxury Investment Index, making it the best-performing asset class of any other type of collectible. AutoFame.com was developed to take your car collection and preservation the extra mile with a growing list of innovative features.

AI-Driven Insights and Narratives

Utilize cutting-edge AI to discover fascinating facts about your car and compose engaging, descriptive narratives that highlight its unique story.

Extensive Data Access

Access vast datasets to populate your car’s specifications, title history, and more, ensuring your records are detailed and accurate.

Comprehensive Documentation

Document key aspects of your car’s history, maintenance, restoration, customization, and performance. Preserve every detail that makes your car special.

Multimedia Cloud Storage

Store photos, videos, and records of awards or special recognition, creating a rich, visual history of your vehicle.

Community Engagement

Join group forums and participate in event postings to connect with fellow car enthusiasts and build a supportive community.

Privacy and Sharing Control

Enjoy complete control over your privacy and sharing settings. Share your car’s legacy through a searchable gallery or on social media platforms with ease.

Mobile-Friendly Platform

Our mobile-friendly platform makes it easy to document and share your car’s legacy anytime, anywhere.

Value Creation

Discover, preserve, and share the legacy of your precious automotive assets to increase their appeal and value.