Correct AC spark plug for 97 C5? Help!

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May 22, 2004 | 11:12 AM

Suprfun

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Joined: Jan 2004

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From: Alpena Michigan

Correct AC spark plug for 97 C5? Help please!

I purchased a set of AC spark plugs from my local dealer and they gave me 41-985 plugs. When I removed the old plugs last night my original's are 41-931. Their parts department is closed on Saturday so I can’t call to double check/exchange. :banghead: The old plugs appear to be burning just fine and the porcelain centers were all a nice tan/brown color. My concern is on the new plugs they gave me (41-985) the center electrode and porcelain are farther out from the base of the plug and would extend further into the combustion chamber. I think it is what is described as an extended tip. So, after all this, can someone tell me if the old 41-931 plugs were superseded by the 41-985 plugs? Will the 41-935's be safe to run in my 97? Will there be a performance loss/gain with the 41-985 plugs? I'd like to get these in this weekend so any help would be greatly appreciated.

Thanks for your time,
Mark :seeya

[Modified by Suprfun, 11:15 AM 5/22/2004]

[Modified by Suprfun, 11:15 AM 5/22/2004]

May 22, 2004 | 11:25 AM

Richin Chicago

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Joined: Sep 2001

Posts: 4,411

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From: Wilmington NC

Re: Correct AC spark plug for 97 C5? Help please! (Suprfun)

Quote:

I purchased a set of AC spark plugs from my local dealer and they gave me 41-985 plugs. When I removed the old plugs last night my original's are 41-931. Their parts department is closed on Saturday so I canÂ’t call to double check/exchange. :banghead: The old plugs appear to be burning just fine and the porcelain centers were all a nice tan/brown color. My concern is on the new plugs they gave me (41-985) the center electrode and porcelain are farther out from the base of the plug and would extend further into the combustion chamber. I think it is what is described as an extended tip. So, after all this, can someone tell me if the old 41-931 plugs were superseded by the 41-985 plugs? Will the 41-935's be safe to run in my 97? Will there be a performance loss/gain with the 41-985 plugs? I'd like to get these in this weekend so any help would be greatly appreciated.

Thanks for your time,
Mark :seeya

[Modified by Suprfun, 11:15 AM 5/22/2004]

[Modified by Suprfun, 11:15 AM 5/22/2004]

Take a look at http://www.rockauto.com what you have is the new iridium plug that Delco has gone to. That is the correct part number. Also they have changed the gap to .040 (pre set on the plug but you may want to check) for the iridium which should be what you are using. I have had the NGK version of that plug in my car for several years and have had good dyno numbers. I think you will be very happy with this plug.

May 22, 2004 | 02:20 PM

Suprfun

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Joined: Jan 2004

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From: Alpena Michigan

Re: Correct AC spark plug for 97 C5? Help please! (Richin Chicago)

Hi Rich,

Thanks for the speedy reply! This sure is a great site for Corvette owners! I'm going to install the plugs and see how they do. Delco must figure by extending the electrode further into the combustion chamber they could cut the gap down to .040 and still end up the same or better than the 41-931 which was gapped at .060. Thanks again for the help.

Mark :seeya

Headed for the garage! :hurray:

May 22, 2004 | 03:24 PM

Richin Chicago

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Joined: Sep 2001

Posts: 4,411

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From: Wilmington NC

Re: Correct AC spark plug for 97 C5? Help please! (Suprfun)

Quote:

Glad to help. Let me know how you do on the driver's side back. I finally took off the coil pack and piping.

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