Right, I've tested as follows:

coil wires? Ok
coil? Ok
coil spark lead? Ok
bad rotar arm? - how could you test??

I put a plug at the end of the coil spark lead and cranked, sparked fine in a pulsed fasion. so that ok'd the first three in the list.

To me this points to a bad dizzy cap/rotor arm, but my old man dissagrees as they look new.

What does the black plug that goes in to the top of the dizzy do??

Could it be the dizzy itself??

Lee