Is the cam timing the problem, or something else?

Ok, cool, then you've tried elevated timing. Did it help at all? If it helped AT ALL, even the smallest amount, then changing the camshaft timing might help even more.
It does help some to increase timing, but I really believe that the cam is still not in correctly. I was hoping to get at it this weekend, but with the recent family development I may have to put everything on hold.