spark plugs on my dad's 02 silverado
 

i changed my dad's plugs today which were the stock AC iridums, 88k on them.

they were hideous, gap was at.080 truck calls for .060, and the white electrode insulation was blue/red/green. but for the 100k plugs they did put a good amount of life out. the truck was used for towing before he bought it so thoes plugs held out some towing too. #8 was a little hard to get to, mine is easier to get to than this one.