[jocko]

Focus on the two pushrods for your suspect #6 cylinder - if they aren't moving the short end of the rocker arm as much as the other pushrods are moving their respective rocker arms, then it's likely a damaged cam lobe. Also, if you had to excessively tighten down a rocker arm on #6 cylinder all of a sudden to make the rocker arm actuate a valve, then that's another indication a cam lobe is damaged. Steve made a good point above - cam lobes don't always wipe to zero, so you can sometimes make the problem appear to have improved by cranking down the rocker arm - but if that is the case, it's probably just a matter of time before it gets worse again, only mitigating a symptom, not fixing it (i.e. the cam lobe face is the hardened part).