SOLVED!....sort of. Where's there's spark.. there's no fire!

"Put a timing light on it and if the timing is wacked then the pick up magnet on the distributor shaft is probably cracked and has moved. Either replace the distributor or install new shaft."

similar problem

Given your erratic timing, a cracked pickup magnet is a definite possibility.

PaulJ2 wrote:

If the distributor body is not slipping at its hold down clamp, and is not slipping at the roll pin/gear, the only place left is the magnetic 8 point reluctor is slipping on its mounting to the shaft.