When building a custom engine ... plugs is 14 mm, although a few older Ford engines used the larger 18mm size back in the '60s. Thread reach does vary, but the two most common flavors are the ...

In racing, spark plugs are practically a disposable ... you usually want the plug gap to be between 0.020 and 0.040 of an inch. Most engine builders seem to settle around 0.035 of an inch.

There’s more to it than that, though. Your engine needs a spark plug that offers the right temperature, gap, and fit to ensure the best performance of your engine. Once you figure out those ...

Keep in mind this may require more than eight spark plugs to index an entire set of plugs for a V-8 engine. The post Tech 101: The J-Gap Spark Plug Advantage appeared first on The Online ...