I don't see as much bow in the lower transom as I do in the "wings" going up the sides and up top. If the cap angles at the back to match the twist of the wings then I guess it was made like that - not sure why though.So as I said earlier, if the transom is flat across the lower portion then you can put a core in the lower and fill the wings. If there is a lot of bow in the lower portion then you have a decision to make. I had a 3/8" inward bow on my 170 that I tried to clamp out with a little success.