Notes:

1. Only switch terminals 1 (internally connected to 3) and 4 are used.
2. The earth is the switched wire, 12v going to the motor.
   
3. The green at the motor is needed for running and parking, the earth at the motor for parking only.
4. One source indicates that this system is also used for their MkI GT single-speed round-bodied motor.
5. To update single-speed systems to two-speed a visibly compatible toggle switch seems to be available from Holden Vintage & Classic. Note that this switch can also be used for lighting, and two-speed heater fans. Especially note that it is cheaper than the recommended lighting switch! Also note that the two-speed switches Bruce Cunha got from both Moss US and Victoria British are not suitable as they do not offer the park function required by the two-speed motor.

Showing the connections. It looks like the spade connector on the green wire should have a 'fin' so it only fits one of the two shrouded spades (the one with the slot in the housing), but replacement harnesses may not. If you get the two coloured wires the wrong way round on those spades the fuse will blow. Get the black and the black/green the wrong way round and the motor will run all the time the ignition is on: (Moss Europe)