JRBrown and Harrym.
JR, I have indexed my spark plugs ever since I could buy the spacing shimms. I've witnessed dyno test using plugs installed as seated and indexed plugs. There is an increase at flywheel HP using the same running conditions. For the street machine you won't realise the change; but I try to do every little trick I can to help my old tub to do better. Consider the small investment and hardly any labor. And it gets you closer to your machine.
HarryM. how can I question your opinion about a subject you feel so strong. You know, the negative electrode igniting the fuel/air mixture. Go ahead and discount the little ole "Flame Curtain".
Happy Trails Beep Beep from Houston.
just old fashion