to the op, I got recommended your thread on bob the oil forum, but didn't feel like registering. what component in the engine do you think the high iron came from during the over heating? it's aluminum block too?
long story but my ls3 end of a track day threw a belt, and over heated very badly. embarrassingly bad really, car went into full shut down mode and set a bunch of codes. but I was 1000miles from home, so I had to put a belt on, bleed the cooling system and drive it home on the baked oil. looking back, it was to thin to start with for a track day during a FL summer lol, 5w30 oil that was slowly dropping idle pressure after every session before that happened from 300deg Temps.
almost stopped and got an oil change on the way home but figured eh, it's going to need rebuilt anyways after that and it's got 120k of very hard miles on it. so I just drove it. sent off a oil sample when I got home and to my surprise it looked decent for what happened. iron was 32. chrome was a bit high at 9. I'm guessing ring wear from abuse?
I realize you're very knowledgeable about these oil tests, i was wondering where you thought the iron in yours would come from, as the ls3 is very similar to the L92?