I'd say it'd fit fine actually. The specs are designed around (presumably) the length of a high end Nvidia reference card - which is exactly 267mm long. If you look at some of the stock photos with this type of "Titan" cooler, there is a little clearance at the end, so I'd imagine a 268mm card will fit without any problems.
Having said that, I'd strongly advise against it. The Hadron has very poor ventilation/airflow surrounding the graphics card area so it's generally advisable to use a reference "blower" style cooler which will self-exhaust a lot of the heat rather than letting it build up. Various posts on the forums here talk about high graphics card temps, high noise levels or both due to not following this advice. Often the same...