Choosing the Right Spark Plugs for Your 1979-1983 GMC G3500
Keep your classic G-series van running strong by selecting the correct spark plugs for its carbureted engine.
- For a stock 1979-1983 G3500, standard copper core spark plugs from AC-Delco, NGK, or Autolite are the most reliable and cost-effective choice.
- The original equipment plug was likely an AC-Delco R45TS; using this or a direct cross-reference is a safe bet.
- Accessing the spark plugs requires removing the interior engine cover ("doghouse"), which can make the job more difficult than on a truck.
- Always check and adjust the spark plug gap before installation; a common range for these engines is .035-.045 inches.
Signs of Failing Spark Plugs
When spark plugs wear out, they can cause several noticeable problems. You might experience a rough idle, where the engine shakes or runs unevenly when stopped. Another common symptom is a loss of power, especially when you're trying to accelerate or drive uphill. Worn plugs can also lead to difficulty starting the engine, reduced fuel efficiency, and even engine misfires, which can feel like a hesitation or stumble during acceleration. Inspecting the plugs when you remove them can also tell you a lot about your engine's health; oily or heavily fouled plugs can point to other issues.
A Note on Engine Access
Remember, on a G3500 van, you'll access the engine by removing the interior engine cover 🎬 Learn how to access the engine and replace plugs on GMC vans., often called the "doghouse." This can make reaching the rear spark plugs more challenging than on a pickup truck. Be prepared to work in a tighter space.
Choosing the Right Aftermarket Spark Plugs
For a 1979-1983 GMC G3500, the original engines were designed for simple, reliable copper core spark plugs. While modern platinum and iridium plugs are available, they may not provide a significant benefit for these older, non-computer-controlled engines and can sometimes be a waste of money. The most important factors are choosing the correct heat range and setting the right gap. The original equipment (OE) plug was typically an AC-Delco R45TS. This is a great starting point and a reliable choice.
Brand Tiers for Your G3500
When shopping for aftermarket plugs, you'll find many options. Here’s a breakdown of how different brands are generally perceived for this type of classic engine:
- Good - Standard Replacement: Brands like Autolite and Champion offer affordable, reliable copper plugs that are a good match for the original engine design. Many owners use Champion plugs in older engines with good results, though some prefer them only for smaller engines like lawnmowers. Autolite is another dependable, standard choice.
- Better - Quality OE Equivalents: NGK and Denso are highly respected brands known for quality and consistency. An NGK copper plug, such as a cross-reference to the original AC-Delco R45TS, is an excellent choice that many mechanics trust for reliability and performance. Denso also provides high-quality alternatives.
- Best - Performance/Longevity (Use with Caution): Brands like Bosch, Accel, and MSD often offer performance-oriented plugs, including platinum or iridium types. While these are high-quality plugs, their benefits are most realized in high-performance or modern engines. For a stock G3500, a standard copper plug from NGK or AC-Delco is often the best and most cost-effective choice. Using a plug that's too "hot" or "cold" for the engine can cause performance issues.
Pro Tip: Stick with Copper
For these carbureted GM V8 engines 🎬 Watch this guide on installing plugs and wires for Chevy 350s., you can't go wrong with a standard AC-Delco, NGK, or Autolite copper spark plug. They are inexpensive, conduct electricity well, and are what the engine was designed for. Save your money unless you have a highly modified engine.
Aftermarket Spark Plug Cost for 1979-1983 GMC G3500
| Category | Price Range (per set of 8) | Notes |
|---|---|---|
| Economy (Skyward, etc.) | $25 - $40 | Basic copper plugs that meet minimum requirements. Suitable for budget repairs. |
| Standard Replacement (Autolite, Champion) | $30 - $50 | Good quality copper plugs. A reliable choice for daily driving. |
| Premium OE-Style (NGK, Denso, AC-Delco) | $35 - $60 | Excellent quality and consistency. Often considered the best choice for stock engines. |
| High Performance (Bosch Iridium, MSD) | $60 - $100+ | Long-life iridium or platinum plugs. Generally not necessary for this vehicle but offer extended change intervals. |
Frequently Asked Questions
What is the correct spark plug gap for my G3500?
The correct gap can vary, but for a G3500 with an HEI distributor, it is typically between .035 and .045 inches. Always check the specifications for your specific engine and the plug manufacturer's recommendation. An emissions sticker in the engine bay may also list the correct gap.
Should I use anti-seize on the new spark plugs?
Yes, it is good practice to apply a small amount of anti-seize compound to the plug threads before installation. This helps prevent the plugs from getting stuck (galling) in the cast iron cylinder heads, making them easier to remove in the future. Be careful not to get any on the electrode.
🎬 See a basic tutorial on how to change spark plugs correctly.How often should I change the spark plugs?
For standard copper plugs in this era of vehicle, a good interval is every 15,000 to 30,000 miles. If you notice any of the failure symptoms, it's a good idea to inspect them sooner.
Is there a recall on spark plugs for the 1979-1983 GMC G3500?
No, searches of the National Highway Traffic Safety Administration (NHTSA) database did not find any recalls or technical service bulletins (TSBs) related to spark plugs for this specific vehicle and year range.
Helpful Videos
![How to install SPARK PLUGS, WIRES + ROUTING KIT video - Chevy 350 GMC Squarebody [Wrench At Home]](https://img.youtube.com/vi/3v883Np61fw/mqdefault.jpg)
Technical Specifications
OEM Part Numbers: R45TS CR43TS 5613957
Engine compatibility will primarily be the 5.7L (350ci) V8, though other V8 options were available. The correct spark plug will have a 14mm thread, a tapered seat, and a .460" reach. The most common OE heat range is equivalent to an AC-Delco R45TS.
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.