gtzy

I purchased a set of cheaply priced "AC Delco" plugs from the auction site. I went to Advanced A/P and compared their A/C Delco plug to the one I purchased. There are several variances between the two.
The terminal nut has a different contour.
The ink printing on the insulator is darker blue.
The appearance of the inscription on the hexagon area.
The metal shell has different configuration.
The overall finish, darker vs shiny, especially noticeable on the ground electrode.
There is a bulge/ring just below the hex area

The images that appear in auction site listing are of the style of plug from Advanced.

After checking on the Advanced A/P website and applying a 20% discount code and $3/plug A/C Delco rebate, the cost difference was about $1.25/plug assuming Delco would not honor a rebate on the cheap plugs.
I'll be returning those plugs and ordering online from Advanced picking up at local store.

Mr. Black

That is interesting for sure. I'm guessing that it just comes down to what ever vendor or contractor AC Delco had build the plugs which I am guessing there is more than one facility. I could be wrong though. I do find it hard to believe that a company would go out of their way to make a fake spark plug.

I just went out and looked at a spare set of plugs I keep in the garage of the same part number you have and they were removed from a factory original 2010 Silverado 1500 that I got good Heads off of.

They all say assembled in the USA with Japanese and USA parts. Have the darker lettering. The hexes say CCP3 what ever that means.

Evil-Twin

EBay has had a strong history of merchants buying counterfeit, or knock offs. Batteries, to memory cards and everything in between. China is the knock off capital of the world. Ebay is their largest outlet. The biggest problem with Cheap goods is as long as the US market buys these cheap knock offs, China will produce more. The cheap stuff from China has no quality control, no oversight. The knock off something, and the variance in quality is all over the place. AS long as people seek only the cheapest price, they will find themself buying junk. Most reputable retail businesses will source their goods from a genuine source. The Port of San Francisco confiscates 5 million dollars a week in counterfeit goods. Agents say its only about 20 % of what gets through.

knewblewkorvette

Yeah, I was just doing some research on spark plugs for my 2002 and saw there was a big difference in prices. Even on eBay, from about $20 for eight to $11 for just one. I also noticed the cheaper ones have part number 41-110 12621258 while it seems the more expensive ones are 41-110 12680072. They are the same plug but only the rebate applies to the more expensive ones.....I think. I'm NOT going to buy the cheap China knockoffs, I'm going to spend the $68 eight pack from a Chevy dealership on eBay, guaranteed genuine GM parts. With the $3 rebate, that will reduce the price to $44.

Evil-Twin

https://www.rockauto.com/en/catalog/...park+plug,7212

laurent_zo6

You spent thousands to buy your car. Why would you take a chance to buy counterfeit parts which could ruin your engine?