Big Block gurus please help

[f.monroe]

Are you positive its a rod knock? I had a 454 truck that suddenly developed a knock. Sounded like a rod but oil pressure was fine .I ran a little top engine cleaner through it and cleaned the combustion chambers out . Knock gone . It was a piece of carbon that had apparently attached to a piston and was smacking the head. Just a thought . There are cheaper ways to clean carbon from the chambers but this one worked.
Frank