Spark plug preference?
Thread Starter
Racer
Joined: Mar 2008
Posts: 435
Likes: 18
From: Northern New Mexico
Spark plug preference?
What is the spark plug of choice? I have a 02 vert that I bought used with 44K on the clock and would like to put some new plugs.
Thanks in advance
Rudy from NM
Thanks in advance
Rudy from NM
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
The GM recommended plug is the AC Delco Iridium plug (replaces the original platinum plug) which is AC Delco part 41-985 and they are correctly pre-gapped at 0.040 ....
Here's the Bulletin announcing these plugs and the different gap compared to the original platinum plugs ....
http://www.acdelcotechconnect.com/pd..._03D-J-171.pdf
Here's the Bulletin announcing these plugs and the different gap compared to the original platinum plugs ....
http://www.acdelcotechconnect.com/pd..._03D-J-171.pdf
Burning Brakes
Joined: Apr 2007
Posts: 966
Likes: 9
From: Phoenix AZ
The GM recommended plug is the AC Delco Iridium plug (replaces the original platinum plug) which is AC Delco part 41-985 and they are correctly pre-gapped at 0.040 ....
Here's the Bulletin announcing these plugs and the different gap compared to the original platinum plugs ....
http://www.acdelcotechconnect.com/pd..._03D-J-171.pdf
Here's the Bulletin announcing these plugs and the different gap compared to the original platinum plugs ....
http://www.acdelcotechconnect.com/pd..._03D-J-171.pdf
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
I just fitted NGK55s and left them gapped at the factory setting. Its running sweet so I'm happy with the choice. No great technical reason for the decision though. Just wanted irridium plugs.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 326
From: CA.
St. Jude Donor '13-'14-'15
For a performance engine--there is no better plug than a copper core design--NGK TR55 seems to be the best for us--Copper is the best choice as they get rid of heat far superior than any other type plug-All the hype about Platinum and Irridium is great for longivity--but as far as performance they are not as good--Be sure to use some never seize when installing the plats or irrd or you will never get them out if you don't take them out for 50K to 100K miles--- PS: You never see racers--Nascar--NHRA etc-ever use anything but copper core--
Drifting
Joined: Apr 2007
Posts: 1,891
Likes: 109
From: Texas
St. Jude Donor '12
You could go with silver plugs and they are supposed to be the best. I went with NGK tr55 and you might as well replace the wires also. I would go with MSD wires. They are the best for the money @ $65. Good luck with whatever you decide to do. 
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Burning Brakes
Joined: Apr 2007
Posts: 966
Likes: 9
From: Phoenix AZ
For a performance engine--there is no better plug than a copper core design--NGK TR55 seems to be the best for us--Copper is the best choice as they get rid of heat far superior than any other type plug-All the hype about Platinum and Irridium is great for longivity--but as far as performance they are not as good--Be sure to use some never seize when installing the plats or irrd or you will never get them out if you don't take them out for 50K to 100K miles--- PS: You never see racers--Nascar--NHRA etc-ever use anything but copper core--
I think it's agreed that the platinum and iridium plugs are meant for longevity...with that said, if I was a racer, there would be no benefit in using an iridium or platinum plug since I'll be tearing my engine down more frequently.
For me, it's woth it to pay more for the iridiums and not have to swap them out as often. Plus, I doubt that there is any noticeable difference when using a copper core plug. Correct me if I'm wrong.
Rocco
Racer
Joined: Apr 2002
Posts: 274
Likes: 0
From: tarentum pa
if you go with the new style gm plug that black z06 recomended, there is also an updated pcm flash that the dealer can put in to optimize the new plugs. its not necessary to do it but it is available.
