Well I came up with the The number of turns head thread Test.
Basically there is a seat in the head for the wider portion of the plugs just above the threads to stop on. This seat, notch, ledge, whatever... read more

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2027 PDRA Schedule Released: Eight Races, Rockingham and Norwalk Back on Tour
The PDRA has released its 2027 schedule. Summit Motorsports Park and Rockingham Dragway are back on the schedule for next year.
NewsSource Today, 02:47 PMMore...