Try retarding the timing back to 4* or so, see if that helps. Also, is your truck points or electronic ignition? I think the 460 that year was the first to get the electronic ignition.

If you copy the link Dennis posted, and remove the file name, that will show you the listing of all of the items he has uploaded. You might find what you need there, or at his FTE site http://mil1ion.clubfte.com/FordRelatedLinks.html