#5612328 14mm spark plug gasket

[Terry M.]

The current iteration of this part number is silver colored and magnetic.
The version in a box marked "AC Spark Plug, Flint, MI" (note no zip code) is copper colored and magnetic.
Same Chevrolet part number and same AC Delco short number. Of course the new box looks a lot different than the old one. Just an FYI for all of you.

[Clem Z.]

the REAL gaskets are solid copper

GM was trying to fool people for years but i guess they have given up.

[Terry M.]

Re: the REAL gaskets are solid copper

Clem,
I don't know how far back one has to go to get the real copper ones, but the lack of ZIP code leads me to think that box dates from before July 1963. I think I have another non-AC box. I'll look for it.

[Mike M.]

Re: the REAL gaskets are solid copper

Terry: was it 63 or 68 ZIP came along? thanks, mike

[Clem Z.]

Re: the REAL gaskets are solid copper

you have to go back to the 20s or 30s for real copper except for race engine plugs so you get good heat transfer. the new tapered seat plugs are now even used in race engines.

[Joe L.]

Re: the REAL gaskets are solid copper

Clem-----

Yes, I'd say the 20s or 30s for copper gaskets, too. I'm certain that no Corvette engine ever used solid copper gaskets going right back to 1953. They were either zinc plated steel or copper plated steel.

[Patrick H.]

Re: the REAL gaskets are solid copper

Mike,

Late 63/early 64 for Zip codes.

Patrick

[Pat #25912]

Re: the REAL gaskets are solid copper

Is part # 1555475 something different again? I have an old (no zip)
AC box of "100 G14MM" spark plug gaskets. They are silver in color.

Pat G.

[Joe L.]

Re: the REAL gaskets are solid copper

Pat-----

GM #1555475 are the spark plug gaskets without the inner retaining "nubs". GM #5612328 are the same but WITH the retaining "nubs. Both part have been around since the 40s and are still available to this very day.

[John H.]

Re: the REAL gaskets are solid copper

Zip codes started in '63 - I remember it happening just before I shipped out to Vietnam in August of that year.

[Terry M.]

ZIP codes

You got it John. According to the USPS history page ZIP codes started July 1, 1963. I'm sure not everyone got on board right away, just like DOT tire markings.