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

Mustang FeedsAt the 1989 U.S. Nationals, a frustrated Ed "The Ace" McCullough drove his Funny Car all the way back to the pits after a tire-smoking loss.
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Leah Pruett and Matt Hagan are ready for the U.S. Nationals. The Tony Stewart Racing teammates both could pick up wins at the Big Go.
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Small Tire Pro Stock and NDRL will trample the track for the NDRL World Nostalgia Drags, Sept. 11-12 at Darana Raceway in Ohio.
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TJ Zizzo returns to Top Fuel racing at the U.S. Nationals. Zizzo is chasing his first win and would love to make it a special one at Indy.
John Force Racing is ready for a big weekend at the U.S. Nationals. All of the teams have their eyes on big wins and titles at the Big Go.
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Chad And Hunter Green Bring Two Funny Cars To The NHRA U.S. Nationals
Chad and Hunter Green will race both race at the U.S. Nationals. Chad chasing championship points and Hunter seeking his first win.
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