Terminology can be confusing with so many different terms used for the same item/task. Has the engine showed ANY signs of life...?

There is no earth wire as such in an old dizzy... the old style circuit is a bit of a daisy chain from the battery through a fuse on to the ign key from there to the coil, through the coil and in your case via to the black wire where it is screwed to the points assembly at the... ALL of which should have sound connections and be insulated from earth/ground up to that point... Until the points close, at which stage the circuit to earth is "generally" accepted as being switched on and the coil charges.

The condenser, is T`d in to the daisy chain at the points wiring termination/screw, and it`s purpose as best I can remember is to cut down the spark across the points to reduce burning of the points themselves, which in time would cause intermittent sparks at the plugs. if the old points are badly burned/pitted then chances are that the condenser is failing. But in your case having replaced both points and condenser should be no problem.

To finish the daisy chain the dizzy is bolted to the engine which it`s self will have a heavy earth wire connecting the engine to the chassis, and the chassis will again have a heavy earth wire attaching it to the battery thus the chain is finally completed, the chain/circuit only making and braking when the points open and close, and thus creating the spark at precisely the correct time.

Any loose or dirty connection in the daisy chain and sparks can become intermittent, and as you have discovered intermittent faults can be a real pain to find.

Any little plastic spacers/washers in the contact breaker/points assembly tend to be insulators and as such can be critical to the switching operation thus must be assembled correctly, though from a dull memory, in the FoMoCo dizzy there is little room for error compared to the Lucas set up of old..

All of which is the low voltage side of the circuit... and once the high voltage/ HT (high tension) has been produced by the coil heading back to the top of the dizzy cap to "distribute" it to the appropriate spark plug, there is room for other issues to arise..

In a bid to determine that the low voltage switching is happening at the appropriate time, perhaps if you removed all the spark plugs an attach one to the HT lead direct from the coil, have it mechanically held/ electrically connected to the engine block and thus earthed... and spin the engine over on the starter........ the plug should spark each time a rush of air is heard/felt to exit each one of the now empty spark plug locations in the cyl head...?

It might be worthwhile to have the fuel pump disconnected at this stage to avoid extra fuel vapours in the atmosphere while messing around with sparks... which if you have a weak heart or are having a bad day... could solve all your problems in life... So be careful.

More than happy to be corrected if any of my thinking seems/is flawed. I have been proven wrong before and will be again...no doubt. For sure there is more than one way to skin a cat and with a timing light or other kit was available, there would be alternative processes.

Good luck.