[BrianG]

Wow, that thing is running rough. Sounds like some serious spark nock or something else going on in there. You might want to try popping the valve covers and seeing if all the rockers are moving up and down. Could be a worn cam lobe, a rocker just loose, or bent push rod. Could also be a jumped timing chain I suppose. Set the timing to spec. Check all the vacuum ports, caps, hoses, etc. again. Another idea which is a long shot and probably far from the problem would be to check the other end. Meaning what do you have for an exhaust. Could there be anything along the way creating a partial plug? Keep us informed on your progress.