All 1996 Corvettes (LT1 & LT4) used AC Type 41-943 spark plugs. I stopped at local Chevy dealer today and that is the only year this particular plug was used. Per the service people there have been no bulletins regarding the platinum tips falling off & this is the only plug recommended by GM.

I have seen many so posts describing the "pucks" coming off LT4 plugs that I know this was a pretty common problem.

GM charges $241 to change plugs, which they say is unnecessary at about 30K miles.

This info leaves me with some unanswered concerns:

1) Is the hocky puck falling off unique only to 96 corvettes or do earlier LT1's using some other AC platinum plug experience same problem. Is it more prevelent on LT4 than LT1??

2) Has anyone pulled plugs on LT4 only to find the plugs were ok?? What mileage?

3)What was different in 96 that a different unique plug was required??

4) Would new AC 41-943 plugs have the same problem as those installed in 96.

5) Bottom line is what plug (Brand & part number) do I install in my LT4 since I do intend to pull the factory originals soon. I know this subject has been beaten to death ( I've searched topic), but I am thinking that what works in a 95 for example may not work as well in a 96, especially LT4. Lots of opinions, so maybe there are several good choices but are there any really BAD choices to avoid??

 

Hey Bud,

I have an LT-1 (92) and I bought a set of AC Delco Professional Platinum #41-904 GM #5614238. Then I read all the stories of the pucs falling off. So, I bought a set of NGK TR55IX plugs and installed them. I'm satisfied so far. I guess what I'm trying to say is there is too much bad press on these plugs to put them in, especially if someone else is going to do it for you.

:flag :flag :flag

 

I agree with Strick,and used the NGK plugs. :steering: :iagree:

 

Thanks for the response, but what you have described is a situation that makes me nervous based on some past experiences with other vehicles.

You use an AC 41-904 in your 92 and an AC 41-943 is used in my 96 (specified by GM for both LT1 & LT4) YET NGK cross references to TR55IX for both plugs. Seems like the TR55IX can't be a "perfect" substitute for both plugs.

Since the GM dealer has said the he doesn't stock the AC41-943 due to limited applications, my guess would be other mfgs may offer a best fit, not necessarily the correct fit substitute for the 41-943.

So I am still wondering if your good experience on your 92 really means it is the best plug for a 96???

 

Okay Bud, It may be time for you to explore the difference between a AC 41-904 and the AC 41-943. I know from the past that Champion uses the numbers to identify heat ranges of their plugs. I don't know about AC Delco, but I'm sure that is the difference between them. Now I think we are splitting hairs here as each engine is different and the way it is driven is different. Can the NGK plug cover a wider heat range? I think it can. Another word comes to mind; compromise. Most of us don't drive the Vette to its limit everytime we drive it. An engine that does a lot of idling would foul if the plug were too cold, but that same plug would be better at high RPMs. Again, we are looking for a "perfect" subsitute for the engine and the way it is driven. I hope this too long explaination might put your mind at ease about the difference between the NGKs and the AC Delco 41-943s. I still worry about those puc coming off.

SEE YA

 

I'm running 41-943's in my 93 which is spec'd for the 96 lt1 and there are no issues with them. I've put a few hundred miles on them with no driveablity issues. Mine is a daily driver both city and highway. When I did the change I had 403's in there so I felt the same way but now I'm ok with the 943's being in there, I wouldn't sweat it unless your a drag racer which it may make a difference, but that is just speculation.

Kitt