This is what my spark plugs looked like. Well the 3 worst ones. I don't think they'd been changed in a very long time. I'm surprised the thing ran at all.
Had 6 AC Delco R45TS's, of which a couple of them had shorter "towers" than the rest. Then 2 were Autolite Platinum AP28's. That was just like my 95. When I tuned it up. It had 3 different spark plug types in it. All the ones that were hard to get to weren't changed at all. I also had 3 different types of wires as well on the IROC that is. Had an 8mm, of some brand, on the coil, one with an orange boot, one that was a cheapy that I can't remember the name of and 6 AC Delco's. Anyway the pic is blurry but you can't even see the electrode on one of them, and the other two were getting close, where build up has closed the gap.

Here's the pic. Cheap camera takes a blurry up close pic.