5 pin for a 4 pin

Only if your ingnition wiring is ready for a 5 pin ECU... tell-tail of that is the dual ballast resistor on the firewall. If you have the single ballast resistor then no it wont work.

You can use the 4 pin in place of the 5 pin but not the other way around (without changing to the dual ballast)

Whenever I have replaced the points to ECU circuit, I always go with the dual ballast circuit so that I dont have to worry about what ECU I throw in it.