I decided to start the failed smog test fix(es) on my 91 with some Seafoam, swap plugs and a new O2 sensor. After the Seaform, pulled the plugs and went to my stash of #5's, some with less than 1K, all with less and 3K, to check 'em out and maybe save myself $40.00. I had never noticed any differences before, but after looking pretty close, I had 6 plugs with a small tip on the end of the electrode. Found some other differences as well (see the photo).
So the question is, did Delco make a couple versions of the #5, or did AZ pick up some bootlegged stuff. Not that it's gonna make much difference at this point, but it'd be kinda interesting to find out.

Subman

Attach file:

---

  DELCO 5 PLUGS.jpg (82.53 KB)

Interesting. I doubt AZ would knowingly buy bootleg stuff. Perhaps AC Delco got an offshore contract and they are some cheap Chinese stuff.

Matthew

Send an email with the pic to AC Delco, and see what they say. Send it to someone in the 'Investor Relations' link; not 'tech service'...

I agree about sending it in. They'd love to know. So would I. So much bootleg shit these days. The logo is the most suspicious part. Those are registered trademarks and should look the same unless Delco changed it at some point.

They've bootlegged everything else.

Pretty sad.