Engine swap

[wellcraftv20step]

Hey guys, i need help again. Yesterday I brought home the new to me 180 hp 4 cyl mercruiser. Afriend of mine will be doing the job with me , he has swaped a couple of boat motors years ago and he builds race car motors, i'm pretty sure i need to change out the transom plate from the old 3.0, aside from that can i get some tips on what to do and not to do to make it go easier, Thanks John,