Our good friend PanteraDoug is probably the most active on this forum, and his postings are indeed long and sometimes very detailed. He contributes a lot. Thanks for that. However, some of his opinions, stated as irrefutable facts, are at best questionable. His posting on plugs above is such an example. He knows for a fact that this and this heat range will foul your plugs, not true, every engine is different, the plug heat recommended should be a starting point. And PanteraDoug states that "you will be happier with the hotter plug every time", yes, but only until it's too hot, then it'll quickly melt your pistons, and then you won't be very happy... And you can't buy plugs based on "99% on the street" if that day on the track will kill your engine, right? You have to get plugs that are not too hot when the engine is really used hard.
PanteraDoug also states that a hot plug will be a rev limiter. It won't, and pinging usually starts at middle rpm uphill in high gear. And while pinging in a classic Mustang can be heard, in a noisy Pantera with the engine behind you, it can be hard to hear. I know that from my boat, I suddenly had a 502 cu in anchor instead of a supercharged marine engine, didn't hear a thing.
PanteraDoug also talks about glazed plugs, if you see that, then you have a serious heat problem in your cylinders. PanteraDoug talks about it as if it's something trivial, it's not.
I agree fully with PanteraDoug on this one:"If the former mechanic mixed 8's and 9' or some combination because of this, then he is either very very tricky and bright OR is very dumb."
PanteraDoug then states that Jon Haas' ignition will fix the problem, and MSD will not. Black and white like that. One system will, the other won't. That's just not reality. I know Jon makes great products, I use a few of them, and he's a super guy, so don't be afraid to buy something from him at any time, but stating as a fact that buying a Pantera-Electronics ignition will fix this, is simply a disservice to Mike, he has enough on his plate right now.
Here's my advice:
Find the physical size of the plug you need, thread, length, conical or not etc. For heat range, look in some charts, buy perhaps the 3 most likely sets. Install the coldest and run the car, idling, driving, flooring it. Remember that with modern unleaded fuels, coloring takes some time, use at least an hour. Read the plugs, all 8 (later when you know that there are no major differences between the 8 cylinders, you can just read 1). If too fouled, one heat range hotter. Repeat. Etc., you get the picture. That's the safe way.
Now I won't tell you what plugs to use, but I can tell you what I've been happy with in my 600HP CHI head'ed engine. The engine builder put in NGK Racing Plugs, and I didn't dare using anything else. Currently I use 5238 and similar with different heat ranges to experiment with. I'm told they give a good protection against overheating and fouling at the same time, which is also my experience, but whether they're better than other brands, I don't know.
If you need more info from me, I'd be happy to skype with you about it. Or you can send me a PM. I'd even fly over and help if you pay the airfare
PanteraDoug, sorry if I put you on the spot, you're not the only one, but some of the advice seen on this forum, can be a disservice to a new owner/inexperienced engine tuner. Let's try to not state our opinions as facts, they're only opinions.