The ships would have to be completly redesigned, the barbettes heavily modified and strengthened, Hull strengthened, (possibly hull lengthened), new engines, new guns, probably increased bilge keels to make the ship steadier, new FI, new superstructure.The turrets would have to be ordered. Look at the Tennessee and the Colorado.
All this is going to cost WAY to much money. And they will still be fuck slow.
You would be much better off scrapping them and building new ships, instead of wasting so much money on an old ship that you are going to scrap in a few years anyway.