64 Dart GT Slant 6 Electric Fan Conversion

Have you upgraded the alternator and charging system first? I have a 13 inch ancillary pusher fan with the probe type thermostat that you can push through the fins, but I put mine in a 1/2 round opening in the core support on the side. I ran constant hot off the positive battery terminal with a spade fuse connector at the terminal inside of wire loom to the fan and have the switched ground lead returning to the thermostat controller mounted were the washer fluid tank used to be. I added in a 65 amp alternator with a 10 gauge wire and 14 gauge fusible link back to the battery connection on the starter relay. As I have done more electrical on the car (relay for power to aftermarket gauges and electric fuel pump), though, I would have installed one of the fuse blocks with the large fuse to go back to the battery terminal on the relay and had extra fuses for other items, but I won't be adding anything else so am okay, for now. As far as fan size, I would go with at least a 17".