Doesn't look like a BIA bolt pattern to meDon't know for what motor but if it's a Merc
ThanksWith the old transom out, you should be able to use a large piece of cardboard or some 1/4" ply to mock up a template. Lay it up against the outside of the transom and line it up with the rivets for the transom pocket. Trace out the side angles of the hull and take a little off to accommodate the inside placement. Keep trimming and test fitting as needed until it drops into place, then trace out the top of the transom curve/cap. Use the template to transfer the cut lines to your doubled up 3/4" transom wood. You may need to account for the angle/bevel at the top of the transom "wings". Test fit before sealing and use the holes in the hull to mark out where you need to drill, paying attention to whether the transom holes need to be drilled at a 90 or angled. I believe most are on the 90, but never done an '87 or newer before.