A second pair of hands and a hoist. Depending on the motor you will use and how far the setback is on your bracket will determine whether or not you can reuse the throttle and shifter cables. You'll probably have to buy a baystar or seastar steering cylinder to keep the hydraulic steering and you'll probably need a new hose for it...
Here are some pics of what it will look like once it's removed:
http://www.wellcraftv20.com/gallery/album102?page=2
Have fun man...