I still think ignition timing is a likely suspect, check it, it won't cost you anything to fix..
Always start with the simple and cheap fixes when trouble shooting.
If you want to check for the valve timing to see if it is way out of time, position the #1 cylinder at TDC compression, then turn the engine a little one way and the the other while watching the rocker arms on #6 cylinder. They should alternate, exhaust closes, and intake opens with not much of a turn either way from TDC.
Might also help us if you can describe how it died, what did it say to you as life slipped away?
Grigg
