hi pgetchell,
I have a large board, it fits thru the pass thru barely. Getting more than 2 boards thru not an option. even two boards might be tight. If you are really eager for pics I could get them possibly. It is baically the dimensions of the rear arm rest. In fact it is the very piece that the arm rest comes out of. ie. You pull out the armrest to access the release for the passthru.