I don't have the figures on the compression or oil pressure; but I have seen engines develop alarmingly loud knocks, which have fooled me into being sure there was major mechanical damage. In at least one (and probably two) of those cases; the problem turned out to be caused by carbon buildup in the combustion chambers (caused by the additives in virtually all modern fuels). For this reason; I would strongly recommend adding a full large size bottle of Chevron Techron Combustion Chamber and Fuel System Cleaner to the fuel tank just prior to filling it up. You'll need to then drive the truck for 50 to 75 miles so this cleaner can do its work. It is worth going out of your way to find this brand; it works better than any other product of its type. Sold at Wal-Mart, Chevron gas stations, and Kragen, Checker, Shucks, Murray, and O'Reilly Auto Parts.
Engine knocks caused by low fuel octane, too wide a spark plug gap, a loose spark plug, wrong spark plug heat range, cracked or dirty distributor cap, crossed plug wires, over advanced ignition timing, excessively rich fuel mixtures, or excessively high coolant temperature often show up in one particular cylinder before any of the others. So I would also consider those issues.