i'm guessing its a chunk of a piston or piston skirt, and that's where the aluminum and silicon is coming from (hyperuretec pistons?) and with that damage on the piston, its now scraping into the cylinder wall, hence the iron levels. it runs perfect for now, but I bet i'm going to be losing compression soon.
Oh well, a bore out 0.030 over and a new cam, port/polish the heads and a set of headers could get this thing running real strong. looks like i will be doing this in the spring.