Spark plug size poll

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stevehuckss396

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Yeah i'm at it again. Trying to get an idea of what the popular size plugs are out there. So a couple quick questions if you have a minute to help.

What size plug/thread in 1/4 scale

What size plug/thread in 1/3 scale


I'm asking because in the case of an older 7/8 threaded plug a true 1/4 scale falls between a 1/4 and #10 and a true 1/3 scale falls between 1/4 and 5/16

1/4 scale 5.5mm
1/3 scale 7.4mm

Also interested to hear about other scales and configurations.
 

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