A spinal interbody fusion implant has an impact rod fitting that is configured and adapted to be connected to an impact rod during implantation of the implant. The implant also comprises one or more openings that are encircled by portions of the implant and that extend into the top of the implant and continue through to and out of the bottom of the implant. The top and bottom of the implant each have a load bearing footprint. Each of the load bearing footprints has a centroid that is closer to the leading end of the implant than to the trailing end of the implant. A method of implanting a spinal interbody fusion implant between two vertebrae of a spine comprises inserting the implant into a patient through a posterior incision and guiding the implant into a position between the two vertebrae using a pair of shims.