Jacob951

changing plugs and wires in my stock 03 zo6 what is recommended? I have seen postings about iridium and also the new E3 plugs? any sugestions?

LannyL81

I need to do this to my '04 Vert as I have no service history. I know I put iridium plugs in two C4s I had, one I still have and they have been just fine.

So I am going to watch this thread closely.....

Vetteman Jack

Last time I did mine I used AC Delco Iridium plugs and GMPP red spark plug wires. I have no complaints with them.

CalF

NGK TR 55 plugs with GM Red 8mm wires.Total cost with tax,less than 100 bucks.

Jacks02

Just did this. You want the latest AC Delco Iridium plugs # 41-110, best price was O'reilly's on sale. They come pre-gapped, so don't change it -- just check 'em. Lightly lube threads with synthetic oil before install.

On wires, best price was through Jeg's, GM #12495519, they come in red for the ZO6, and cost much less than a coup/convertible black wires -- go figure.

I'll not cite cost here as it could have changed within weeks, so check yourself. Good luck with your install.

A recent "stealer" story:

My car was running rough at 36K miles, DIC said "misfire." Same minimal reading at an O'Reilly store, so went to Gilcrist Chevrolet in Tacoma, WA, to see if their better GM electronic test equipment could verify suspected bad gas. Instead, without telling me, a Tech put in 3.0 hours investigating, and said "I don't know what's wrong with it, but I could start by installing new spark plugs."

With military discount, they charged me $300 for the "analysis." Then they offered me to change the plugs for, get this, $600 because "...the book says it takes 3.5 hours labor."

I installed new plugs and wires in 90 minutes (my first time on a C5), and the car runs better than when it was new. Parts cost was about $85.00.

Moral: Stay away from stealers, do your own work if you can, and enjoy the results!

SilverC54me

Did this on mine. Change every 50k or so, cheaper than the Iridium plugs. Plus you do not want the plugs to be in the engine forays long as gm says. The plugs can size in the threads, this does depend on use and weather conditions.

Gary

Pounder

Pounder

No E 3 plugs !!!!!!!!!!!

hoosiervette

Curious as to why not. I don't know anything about them.

nsogiba

GMPP Red wires and TR55 plugs on mine, no issues and very cost effective.

Pounder

junk, you will end up replacing them !!!!!!! I am a firm believer of what GM recommends !!!!

blacksedan87

We use NGK TR55 (p/n 3951) and the GM hot wires all the time with great success. The thing to remember however, the NGK plugs are copper based plugs and should be changed about 25 - 30K miles. If the vehicle is high horsepower (forced induction, heads/cam) we use a slightly colder plug - TR6 with the same great outcome.

mrm13

I am a little confused about the NGK plugs.
I wanted to change mine last week. Went to NAPA and asked for TR55. These are completely wrong gap as I asked to check them tight at the counter. The correct ones are TR5. Yet time after time I see people call them TR55 on here.

blacksedan87

I think you are confusing gap with heat range. Gap can be altered and measured. Heat range is the length of the insulator. The lower the number, the hotter the plug. So a TR5 is hotter than a TR55.

We typically gap TR55's to around 40 thousandths.

RoninC5

For all I know they are factory installed or at least 12 years old on my 99. Runs like a champ though...

mrm13

When I put my headers on, I ordered from Hinson new engine mounts and asked for a new set of wires and plugs. What I received were NGK TR5 V-power.
When I went in Napa, I did as advised on here and asked to open every plug and measure the gap before I buy them. Why?
Because according to the manufacturer, their plugs are pre-gapped and should not be messed with. The LS1/6s in the Corvettes are supposed to be 0.40 gap. The TR5 are factory gapped at 0.39. The TR55 are gapped at 0.59 and both are the same heat range. It's recommended to only change the pre set gap by ten thou either way. So for the TR5 you can run it between .029 to .049 and the TR55 is good for .049 to .069.
Since the LS1 likes a .050 gap, you could really run either plug and you'd be fine. But the TR5s are what comes as a factory spec.

0MarylandSpeed

I like MSD wires and NGK TR55s.

hoosiervette

Thanks. Have you used them before?

NMYDNA

I ordered these yesterday. Thanks Jack for the vendor info.

Jacob951

I ended up going with MSD wires and iridium 41-110 plugs and she runs great especially since I think the wires and plugs were original from the factory, Yeah bad shape!