That sucks Kalli. I'm curious to know what you find when you start looking deeper to see what happened. I bet it is a rod bearing too, but that is just a guess.

 

really wonder what happened there. sounded a bit like a rattle and then that noise you get if you remove a single spark plug from a running engine. buddy said I might be lucky and it's a (or a few) collapsed lifters. somehow I still believe it's to do with the heads ... i never pulled the rocker covers. I didn't want to see it yesterday.
Anyway i'm looking into bringing it back end of next week and then start pulling it apart.. i'll keep you updated