2004 280 sundancer stereo mount

Hi I bought an 04 280 sundancer on Halloween the boat is 200 miles away from me and I am updating the stereo can someone tell the size of the piece where the stereo and cd are mounted.
Thanks

 

Yes it has factory clairon in it with the disc changer. I’m removing all that and would like to know the dimensions of the piece of wood that the radio is mounted to so I can get it ready before I head up to the boat