ballast resistor question

If you use the later "4 pin" ECU you can use the "points" ballast

The early "5 pin" ECU required a 4 pin ballast. A later 4 pin ECU only needed a 2 pin ballast. You cannot tell by looking because many 4 pin ECUs (mostly aftermarke) still have 5 physical pins. You an only tell in that case by using an ohmeter to check resistance on to the 5th pin.