It's the same as the regular procedure for getting and reading the color on plugs, except that the plug threads are cut back to get a better look at the mixture ring at the base of the center electrode ceramic.
In this case I would say that a cheap wideband O2 would be more useful.
It seems that lots of people (erroneously?) refer to cutting the ignition after a test run as a "plug chop." I had never seen this usage until I Googled it.
please tell me the engine has been tuned? haha you have a boosted h/c/i v8, get a damn wideband! I'd trust my wideband more than doing a plug chop but that's just me...