Usually when the problem persists, we tend to "over think" the problem. Stop everything....and start over simple.
Check your battery and grounds. Is your engine grounded to the body and/or chassis? Check the wiring and verify voltage to coil/distributor. Plug gaps, valve adj.etc.
Stop looking at everything you did and just start over and rethink it like it is a different vehicle. When things get difficult, many times it turns out to be something simple.
