Ya, I was reading about them with the search function earlier. There was a Napa part number listed. I didn't quite understand how they worked, but with your explaination of the plug it has become clear.
Thanks again, I'll check it out.
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Adversity doesn't test your character; it reveals it.
71 C-10 LWB 350/TH350. I purchased it in 1978 for $1400. I'm currently abusing it daily. (when it's running

)