Autolite Copper Core spark plugs deliver quick starts, good fuel economy, and smooth acceleration. The copper-glass seal bonds insulator and terminal post center electrode together to ensure full required voltage at spark gap, creating a gas-tight seal that is 100 percent leak-proof. Copper Core spark plugs feature a cold-formed steel shell and precision rolled threads, and a one-piece terminal post that adds strength. The multi-rib insulator reduces the danger of "flash-over" to prevent misfires, and the resistor reduces radio frequency interference (RFI) and electrode erosion. The full copper core electrode provides better performance in all conditions. Autolite Copper Core plugs are your industry standard.
Autolite Copper Core spark plugs deliver quick starts, good fuel economy, and smooth acceleration. The copper-glass seal bonds insulator and terminal post center electrode together to ensure full required voltage at spark gap, creating a gas-tight seal that is 100 percent leak-proof. Copper Core spark plugs feature a cold-formed steel shell and precision rolled threads, and a one-piece terminal post that adds strength. The multi-rib insulator reduces the danger of "flash-over" to prevent misfires, and the resistor reduces radio frequency interference (RFI) and electrode erosion. The full copper core electrode provides better performance in all conditions. Autolite Copper Core plugs are your industry standard.
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The current lowest price is $7.29. The all-time low was $3.40 on 12 July 2025 — today's price is 114% above the lowest ever.
Prices last updated 7 June 2026.
Autolite Spark Plug 3923
Autolite Copper Core spark plugs deliver quick starts, good fuel economy, and smooth acceleration. The copper-glass seal bonds insulator and terminal post center electrode together to ensure full required voltage at spark gap, creating a gas-tight seal that is 100 percent leak-proof. Copper Core spark plugs feature a cold-formed steel shell and precision rolled threads, and a one-piece terminal post that adds strength. The multi-rib insulator reduces the danger of "flash-over" to prevent misfires, and the resistor reduces radio frequency interference (RFI) and electrode erosion. The full copper core electrode provides better performance in all conditions. Autolite Copper Core plugs are your industry standard.
Autolite Copper Core spark plugs deliver quick starts, good fuel economy, and smooth acceleration. The copper-glass seal bonds insulator and terminal post center electrode together to ensure full required voltage at spark gap, creating a gas-tight seal that is 100 percent leak-proof. Copper Core spark plugs feature a cold-formed steel shell and precision rolled threads, and a one-piece terminal post that adds strength. The multi-rib insulator reduces the danger of "flash-over" to prevent misfires, and the resistor reduces radio frequency interference (RFI) and electrode erosion. The full copper core electrode provides better performance in all conditions. Autolite Copper Core plugs are your industry standard.
Last updated at 07/06/2026 23:29:29
Autolite Spark Plug 3923
Delivery between 10–15 June $9.99
1 x AUTOLITE Copper Core Spark Plug 3923
Delivery between 11–15 June $15
8 X Copper Core Spark Plug For Land Rover Range Rover L320 L322 428ps
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
originally posted on autozone.com
Well at first I wasn’t really impressed as far as increasing the performance on my 5.2 L 318 Dakota. Started it, drove it around the block, and thought it was running pretty sluggish. Then I realize that I had to plug wires hooked up incorrectly at the distributor(thank God I wrote cylinder numbers in black marker on the boots and the distributor. Got those two wire switched around and “hold on your lugnuts!”. Pretty incredible difference between the recommended OEM plugs And these copper Autolites.
originally posted on supercheapauto.com.au
Good replacement for your spark plugs. I replaced original plugs with these on 2014 vehicle.
originally posted on autozone.com
Great plugs. Run them in a 408 Windsor. AFR recommends 3924 as a good starting point
| Thread Size | 14mm X 1.25 |
| Reach | 3/4" |
| Hex Size | 5/8" (16mm) |
| Seat Type | Gasket |
| Tip Configuration | Mid Projection |
Autolite Spark Plug 3923
Delivery between 10–15 June $9.99
1 x AUTOLITE Copper Core Spark Plug 3923
Delivery between 11–15 June $15
8 X Copper Core Spark Plug For Land Rover Range Rover L320 L322 428ps
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
Well at first I wasn’t really impressed as far as increasing the performance on my 5.2 L 318 Dakota. Started it, drove it around the block, and thought it was running pretty sluggish. Then I realize that I had to plug wires hooked up incorrectly at the distributor(thank God I wrote cylinder numbers in black marker on the boots and the distributor. Got those two wire switched around and “hold on your lugnuts!”. Pretty incredible difference between the recommended OEM plugs And these copper Autolites.
Good replacement for your spark plugs. I replaced original plugs with these on 2014 vehicle.
Great plugs. Run them in a 408 Windsor. AFR recommends 3924 as a good starting point
They're cheap but they do the job, in hindsight I would have forked out the bit extra for Iridium tipped so I don't have to change these ones after 20,000km. Fits the Ford Territory 6cyl engine fine.
The Toyota was acting strangely. It felt like another $300 plus bill coming on. The clerk at O'Reilly's helped me by scoping the car for free and finding the best spark plug for my budget and car. The Toyota runs great now with the help of O'Reilly's and YouTube.
Good, low-cost plugs for a vehicle that frankly isn't worth spending more money on. Don't get me wrong, these plugs are very good quality. I'm just happy that they didn't "break the bank" while doing a great job of making my beater run more smoothly and with a slight increase in power.
These plugs can be used for BMW R1100RT’s instead of the priceier OEM plugs and are usually more available to the rider if plugs are needed. Carry an extra set with you for insurance.
Autolite spark plugs used on 1992 Ford Mustang convertible. 5.0 with Vortec supercharger. These have a longer reach for aluminum heads.
I prefer Champion but these are doing the job fine. Beats NGK, but what doesn't.
My schedule recommends changing out plugs every 30 thousand miles. These autolights cheapos are fantastic. NGK were the ones installed at factory and Autolights far exceed there performance. I know they exceeded fuel milage since I bought this vehicle brand new and now with autolights get 2-3 miles more then original in city driving per gallon. Highway about 3 miles more then NGK
| Thread Size | 14mm X 1.25 |
| Reach | 3/4" |
| Hex Size | 5/8" (16mm) |
| Seat Type | Gasket |
| Tip Configuration | Mid Projection |
