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 FeedsMatt Hartford is having a career-best year in Pro Stock this season. Hartford's approach to business and racing has fed his success in both.
Cutting a good light is how you win races but that could be changing. GM has filed a patent for a camera-based launch control system.
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The controversy over Mack Racing vs Team White Rice spilled over on social media. Here's what we know about the situation.
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The NHRA Las Vegas Nationals always puts on a great show. Dragzine's Mark Riker grabbed these great images from The Strip.
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The NHRA has named Mitutoyo as its official precision measurement partner. The partnership will run through the 2029 season.
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Recent Technical Articles
Put Boost On Display With The New S650 System From Hellion Turbo
The new R-Series twin-turbo system from Hellion Turbo moves the turbos to the top of the S650 Mustang engine bay for 1,200 horsepower.
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