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 FeedsSpencer Hyde is in the 2026 PlayNHRA All-Star Funny Car Callout at the U.S. Nationals. He?ll race a star-studded field for an $80,000 prize.
The Factory Stock Showdown field at Indy is stacked with great racers. Jonathan Allegrucci is trying to seal the points title at the Big Go.
Frank Hawley's Drag Racing School has trained thousands of racers. Hawley is now back in the ownership seat of the school.
More...
Selecting the right crank and rods for your boosted engine is critical. We explore what you need to know to pick the right parts.
More...
Chad and Hunter Green will race both race at the U.S. Nationals. Chad chasing championship points and Hunter seeking his first win.
More...
Recent Technical Articles
NHRA U.S. Nationals Friday Qualifying: Langdon And Beckman Lead The Big Go
Qualifying kicked off Friday at the U.S. Nationals. Langdon, Beckman, Stanfield, and Smith took the provisional No. 1 qualifying spots.
NewsSource Yesterday, 05:50 AMMore...