74 Dart Swing 225 Electronic Ignition Module

You don't need a 5 pin, and for years now, just about all replacement ones have been 4 pin. The 5th pin is supplied power via the second half of the ballast resistor. You can use a 4 or 5 pin module with a 4 pin ballast, but you can only use a 4 pin module with a 2 pin ballast.