Spark Plug, Wires, Header Clearance

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Jul 28, 2025 | 11:56 AM

obxracer

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Spark Plug, Wires, Header Clearance

Hi All - Complete noob here. I bought a car with a modified LT1 (a few details in signature). I have general mechanical experience but mostly with various 4 bangers.
The plug wires in general have very little clearance to the header. The number 7 is so tight it's burnt and arcing periodically. The wires are branded Scott (seems to be a good choice). The plugs are NGK TR55. I don't know anything about header. The head is Edelbrock Performer.
The shop that built the motor doesn't have a specific recommendation. They said the owner had another shop install the header and I have no info about it.
Does anyone know if there is a spark plug with a shorter insulator that would work? Anyone have plug wire recommendations?

Jul 30, 2025 | 03:54 PM

BALLSS

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Accel makes a shorty plug. You can also buy porcelain plug wire ends. Currently you will have chronic misfires from plug boots burning/arching against headers you have

Aug 1, 2025 | 08:36 AM

obxracer

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Thanks ****** - Just steering me to Accel was a huge help! Took a bit of digging from there to find the best cross match to the NGK TR55 that came in the motor (and seem to be a popular choice). Looks like the Accel ACC-P526S.

Next question: What are opinions on running just one or two of the P526S and the rest TR55?
A set of 8 is approximately $240.

I'm still getting details worked out for a custom set of wires. Scott Performance Wire seems to offer them at a good price - especially for a custom order.