How can I use 2010 graphics card on 2011 model (27 inch)?

Hi, I am trying to use a 2010 27 inch iMac (EMC 2390) graphics card (Radeon HD 5750) on the 2011 27 inch model (EMC 2429). The screen does not turn on after powering on. Any one knows is it still possible to do so, by flashing ROM or something?