Hey everyone, I'm currently running Navarro heads on my 8BA and using Autolite 216 plugs. What are some plug options that will not be too long or short for my Navarro heads? The 216's appear to have short threads but not sure if I can go to a .75 thread length or not. If you run these heads, please chime in with your fav plug choice. Thanks in advance fellas!
Thread length in the head makes most of the decisions. Autolite 216 is a popular flathead choice. The engine will indicate what it likes. Providing carburetion and ignition are set correctly a healthy plug will show a mid to light brown colour. Use plug colour to dictate your next move. Most heads place the plug directly over the valves, ruling out plugs with extended nose set up. That said, there are a few heads where the plug location is moved away from the valve, giving a greater choice of plugs.
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