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 FeedsEngineered with a third line of elliptical bushings, this SEMA award-winning Mustang differential brace works with factory coolers.
More...
Powered by a Whipple-supercharged Gen 4X Coyote V8 and managed by a FuelTech ECU, this composite Shelby delivers 1,000 horsepower.
More...
Matt Hagan is chasing his fifth NHRA title. Leah Pruett wants to end her latest Top Fuel run on a high note with a big win.
More...
Bill Bader Jr is stepping up to the plate to help grassroots racers. Bader has launched the Sportsman Racing League for bracket racers.
More...
John Force Racing could have a huge weekend at the NHRA finals. Vandergriff and Beckman could have career moments at Pomona.
More...
Recent Technical Articles
Short Circuit 2026: Drag-And-Drive Mayhem At George Ray?s Wildcat Dragstrip
The Short Circuit 2026 put on one heck of a show. Drag-and-drive racers hit the track at George Ray's Wildcat Dragstrip.
NewsSource Today, 01:30 PMMore...