Better advice is given above than I can give, but Tx Firefighter most likely solved your charging problem. Take out your old voltage regulator.
One-wire alternator "get exited" at different rpms. Mine starts charging between 900-100 rpm (it has ben working fine for over 8 years).
It sounds like you have hydraulic lifters ("..backed ALL of them off a half turn")? Are they hydraulic or mechanical? Who set them? Were they set hot (after 30 minutes of running, after reaching max temp)? If they were set cold, they will most likely be too tight and should be reset.
Keep trying and keep reporting back.
