A system for delivering bone graft material during spinal interbody fusion comprises an interbody fusion device implanted in a spinal intradiscal space. The device has a distal end, a proximal end, opposing spaced side walls and opposing top and bottom surfaces defining a hollow interior A channel extends through the proximal end in communication with the hollow interior. An elongate guide pin is releasably attached to the device proximal end. An elongate cannula has a first lumen extending therethrough, the cannula including a mating feature at a distal end releasably secured to the device to substantially align the first lumen with the device channel. The cannula includes an axially offset receiving member receiving the guide pin and an axially spaced retention member securing the cannula to the guide pin and the device. A tamp advances graft material in the first lumen into the device through the channel.