another pic

its rich ...you kinda want a tan porcelin and like in the pic of titans plugs you want the outer ring to show it is building alittle heat going out the backside [metal colored] then the darker color behind the bend of the strap which is away from the heat...look at titans plug and note how the outer ring goes from metal color too the darker color and that shows it making power or building heat out the backside of your pass ...hope this helps ...once you get too lean the whole outer edge will be metal colored just for reference which gets on the edge of being too lean of a tune which makes power but gets dangerous and close too detonation...at this point you will see grey specs on the porcelin....


btw....alky plugs are harder too read exspecially from pics !

If your Purging on the same plugs your trying to get a reading on, it's not going to happen.
Make your Pass, kill the Motor at the end of the pass get your reading there, and take a pic b 4 returning to the Pits. Don't purge on the same plug your tunning on as it defeats the purpose of trying to get a accurate reading. And then your will need to do a plug chop to actually get a good reading or buy the correct tool to read the bottom of the Porcelen by the threads. It's hard to tell what kind of reading your getting if I read your Post correctly, that your purging on the same plug your making a pass with.
If I missread the post sorry.

Here you go.

http://www.pro-system.com/sparktool.html

You read right parts. I did purge on these. Got some new plugs yesterday these will be my new purge plugs. Still trying to learn how to tune with plugs.

I have actually read that people purge there motors once or twice during a race. They say its be/c the purge fuel in the bowls will build heat faster on the run and before the end of the run the purge fuel is out of the system and is running on alky.

You have to keep in mind that your putting in approx 1.5 times as mush Gas as it can actually burn, so with that thought in mine it has a tend to foul the plug more than give it a hot burn.
When I purge I generally run the motor till I get most of the Purge Gas out of the Carb Bowls. Once it starts to run out of Gas I kill it.
Then when I put the Alky Plugs back in it I am starting back with fresh alky plugs.