New Transom worried about Bracket problems

[Hoover]

Ok,here goes. I am ready to put the new transom in and I am going to use plywood. I want to make the transom full with a bracket(150 Yamaha 20 " shaft) hanging on it. I have a stainless marine bracket a buddy gave me. My fear is this. That bracket is heavy, I am thinkin at least 75 pounds. Motor ways 395. Am I foolish to think that all of that torque and weight sitting back there will be too much for my new transom. For what it is worth I am doing the transom exactly as Strick did his in the here we go again post. Also is there a problem where when I come off plane I may have to move to the front of the boat to keep the motor from swamping.