340 valvetrain help

So when you say 'knocking', do you mean a heavy metallic knock like in the bottom end, or a high pitched, erratic and rattly type of knock, like ignition knock or pinging? And does this occur only when accelerating or at all times in the 1500 to 2500 rpm range? Trying to figure out what 'knocking' you mean exactly....Did it change/go away after you retarded the timing?

Nice color BTW..