best guess

[Orodi]

I was out in the mustang on saturday and something weird happened I was romping on it a little and then i heard a wierd clunking noise it sounded like it was coming from under the D.S. valve cover i pulled them off expecting a loose or broken rocker and nothing was wrong....I check the compression on all 8 nothing wrong...head gaskets are fine...i was thinking either the lifters or the valve cover came loose I'm lost on this one. Any ideas?

[RACEME]

Is it missing out? you may have collapsed a lifter.

[Orodi]

it wasn't missing at all like i said there was nothing out of the ordinary outside of that clunking noise....i'm thinking it was the valve cover itself