Instruments and methods for preparing an intervertebral space for receiving an implant. An adjustable trial implant has an adjustable stop mechanism having a stop member connected thereto to vary the distance that a body portion of the trial implant can move into the intervertebral space. Cutting tools for forming cutouts in the adjacent vertebrae use the trial implant and/or a guide to position a cutting tool which may be a burr or a chisel. The chisel cutting tool can be moveable relative to a selected trial implant or the chisel cutting tools can be fixed onto a trial implant shaped body portion.