My 1703 has four of these spacers in each wheel well, each of a different thickness. There is a steel plate fastened with wood screws to each spacer. The large holes are for the head of plow bolts that secure the assemblies to the well. I did not find a ready source for plow bolts, so I used elevator bolts instead; they have the same large head but are flat instead of crowned. One of the spacers was too thin to accept screws, so it was attached with countersunk rivets (OEM). I hope you have the special spacers for the bottom of the well, as they are a different profile and held in place with countersunk stove bolts.