A Comprehensive Guide to Spark Plugs for the 1981-1986 Dodge D350
Keep your classic Dodge truck's engine firing on all cylinders with the correct set of plugs.
- Stick with standard copper core spark plugs from brands like Champion or NGK for the best performance in your D350's stock ignition system.
- Avoid platinum and iridium plugs, as they are not well-suited for the original ignition and may cause a weaker spark.
- Always verify the spark plug gap is set to 0.035 inches before installation.
- Replacing spark plugs is an easy and inexpensive DIY job that can significantly improve engine performance and fuel economy.
Symptoms of Failing Spark Plugs
Worn-out spark plugs can't create a strong enough spark. When this happens, you'll notice problems with how your truck runs. Ignoring these signs can lead to poor fuel economy and put extra stress on other ignition parts.
🎬 Watch: 9 common symptoms of failing spark plugs explained.- Rough Idling: The engine may shake or vibrate more than usual when stopped.
- Engine Misfires: You might feel a hesitation or stumble from the engine, especially when accelerating.
- Poor Fuel Economy: If you're filling up the gas tank more often, bad plugs could be the cause. Incomplete combustion wastes fuel.
- Hard Starting: The engine may take longer to crank before it starts, or it might not start at all.
- Reduced Power: Your truck may feel sluggish and slow to accelerate.
Choosing the Right Aftermarket Spark Plug
For the 1981-1986 Dodge D350, the original ignition system was designed for standard copper core spark plugs. While newer technologies like platinum and iridium exist, they often provide no benefit and can sometimes perform worse in these older, lower-voltage systems. Sticking with a quality copper plug is the most reliable and cost-effective choice.
Brand Tiers for Your D350
Tier 1: OEM-Equivalent & Highly Recommended
- Champion: Champion was a very common original equipment supplier for Chrysler products of this era. The Champion Copper Plus is a dependable, factory-style choice that works very well in the 318 and 360 engines.
- NGK: Many Dodge truck owners have had excellent results with NGK V-Power plugs. They are known for high quality and can sometimes solve minor idling or running issues that other plugs don't.
Tier 2: Solid Aftermarket Choices
- Autolite: A popular and affordable option. While many users have good experiences, some have reported occasional quality issues out of the box.
- Denso: A well-regarded brand that makes quality standard-type plugs suitable for the D350.
- Bosch: Bosch offers standard copper plugs that are a reliable choice for these trucks.
A Note on Platinum and Iridium Plugs
It is generally best to avoid using platinum or iridium spark plugs in your 1981-1986 D350. These plugs require a higher voltage to spark correctly, which the stock ignition system may not consistently provide. This can lead to a weaker spark than a standard copper plug, causing performance issues. Stick with copper for reliable performance.
Cost of Aftermarket Spark Plugs (1981-1986 Dodge D350)
| Plug Type | Price Range (Per Plug) | Best For |
|---|---|---|
| Standard Copper (Recommended) | $3.23 - $5.50 | Stock performance and reliability |
| Platinum / Iridium | $6.00 - $16.38 | Not recommended for this vehicle |
Pro Tip: Check the Gap
Always check the spark plug gap before installation, even if the box says they are "pre-gapped." The correct gap for most D350 engines is 0.035 inches. A simple gapping tool is an inexpensive and essential part of the job.
🎬 Watch: How to correctly gap your new spark plugs.Frequently Asked Questions
How often should I change the spark plugs on my D350?
For standard copper spark plugs, a good interval is every 20,000 to 30,000 miles. Given the age of these trucks, regular tune-ups are key to keeping them running well.
Is it difficult to change the spark plugs myself?
No, this is a great DIY job for beginners. Access to the plugs on the Slant-6 and V8 engines is generally open. The job requires basic hand tools like a ratchet, a 5/8" spark plug socket, and extensions.
🎬 See this step-by-step spark plug replacement on a Dodge Ramcharger.What is a spark plug non-fouler and do I need one?
A spark plug non-fouler is an adapter that moves the spark plug slightly out of the cylinder. It's used on older, worn engines that may be burning oil, which can coat the plug and cause it to misfire. If your plugs are constantly getting fouled with oil, a non-fouler can be a temporary fix.
Do I need to put anything on the new spark plugs?
Yes, it's highly recommended to apply a small amount of dielectric grease to the inside of the spark plug wire boot. This protects against moisture, prevents corrosion, and makes it easier to remove the wires in the future.
Helpful Videos
Technical Specifications
Spark Plug Gap: 0.035 in (0.89mm) Plug Type: Standard Copper Core Recommended Socket Size: 5/8 inch
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.
- Dodge D350: