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Spark Plug Gap...What's Correct?



Hi guys -

Can someone please tell me what the correct spark plug gap should be on a '93 LT1?

Also, any ideas on what would cause the tiny electrodes on the spark plugs to disappear over time? That is sort of strange to me. ;help

Hib Halverson

Technical Writer for Internet & Print Media
Jan 10, 2001
CenCoast CA
71 04 12 19
Plug gap for 93 is .050.

If the platinum pucks are missing from the spark plug---a common problem for the first couple of years GM used double-platinum plugs--you need to replace all 8 with new ACDelco plugs.

If you drive you drive your Corvette easy or normally, use the 41-906.

If you drive your car hard and it nevers sees starts without warm-ups, use the 41-913.

While I do not have much personal experience with them so far, based on some research I've done, I think Denso has a great high-performance plug in its "Iridium Power" line. The ones to use in LT1s that are driven normally are the IT16. If you drive hard use the IT20. Lastly, if you want the OE equiv. plug in a Denso, use the PT16EPR-L13.

If you don't care for the ACD or Denso spark plugs try the NGK TR55VX for normal driving or the NGK TR6 for aggressive driving.


Thanks Hib...

That's very interesting. I did not know that it was a common problem, just thought I had a strange car. :crazy Having that tiny piece gone made the gap too large, which I was told would have retarded the timing. All along I have felt that the car ran very strong, maybe I was wrong.

I thought the mechanic said that when he pulled the plugs the gaps were actually .070. I was surprised.

I went ahead and had the stock plugs put back into the car - A/C Delco platinum. I get on the car once in awhile, but nothing real aggressive.

Thanks for the input.



I notice on my 85 L98 that my gap was to long and all it really affected was how easy it started

didn't really do much of a power thing or a idle thing

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