These engine mounting plates should fit most late model GM LS style engines (4.8, 5.3, 6.0, etc.)  and will give you a great base to start your custom motor mounts off from.  They are manufactured from 1/4" plate steel, the holes are .469" diameter, the hole spacing is 4.430" center to center and 3.064" center to center. These are sold in pairs and unpainted.