If the case has good airflow where the graphics cards are, use an aftermarket cooler (e.g. EVGA ACX 2.0). If the case doesn't have great airflow where the graphics cards are, use a reference style 'blower' cooler. I would recommend two aftermarket cooler graphics cards, as the 760T has great airflow if you keep all of the fans in, and to help, you can buy brackets which go in an un-used PCI slot, then you can mount two fans, so you're blowing air straight into the rear exhaust, which will take all the hot air out.
Aftermarket coolers are quieter, faster and they run much cooler if you have good airflow, which the 760T does, though I would still recommend getting one of those PCI brackets. You can also overclock aftermarket graphics cards by quite a bit, so they can run much faster.