it definately sounds like the ignition timing is out.
you say you have changed the dizzy and metering unit. why? what was wrong with the original ones?
stand by the passenger wheel, so that you are looking at the dizzy,
start with number 1 at the top, work anti clockwise. if no good, try putting number one at the bottom but still working anti clockwise.
i had similar problem with a conversion i done a few years ago.