Ok I know to some that spark plugs are a bit of a preference item, almost like oil, maybe as bad as bias vs radial. I'm not about that with this. Searches show a preference for Autolite 216s but almost nothing for AL7s. The Ford part#, 7RA 12405 is spec'd out for 38-48 Ford/Mercury. Is it that they're just a tough number or type to find? I'm not looking for "...forget those ****ers and just run blah blah blah...", I'd actually like to hear some solid experiences or knowledge. Why? I have 3 sets and a 59A so that's why. And as always, thanks in advance.
If they fit, give them a try. First set of plugs I put in my flathead were the "hot ticket" according to the 'net. But they got their electrodes flattened by the valves. I can use Champion H10's if I can find them, but now use some Autolites because they are easy to get. But every engine should probably be tuned for a particular heat range and plug. You might find someone else's favorite isn't right for your engine.
I run champion H 12 plugs [512] they are one heat range hotter and I do that because I run stock jetting on the dual 97s and we are about 3900 ft, I prefer to be a bit on the rich side and they do not foul , so when I travel to lower al***ude it's all good. this set has been in since 2017.
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