Piston pin bad ?
There are small bits of piston that have chipped off all over top of the piston.
The knicks in the valves and chamber are probably from them.
As far as the noise... I believe a previous poster was correct in thinking that it was the
siezed rockers hold the valves open then slamming shut. This would explain the clanking noise , the lean condition and the rough idle . It would also explain why I thought the engine seemed to be running rich while burning #8 piston..