The block goes on top of the strap with the slopeing bit facing forward so the strap gets a smooth bend, as you tighten the bolt the block pushes down on the strap if that makes sense. If when you tighten the bolt it goes all the way to the bottom the strap has stretched and will need replacing. I would check the dolphin striker bolts as well and the beam should have about 10mm prebend. I would take those two back blocks off they might have been for an old spin, if you put a new spin on they would go on the front beam, post as many photos as you like for us to check and welcome to the forum, you have an awesome boat that will come up well with a polish