Getting a '77 20' CC SeaCraft redone

[McGillicuddy]

Nice fishes. Unfortunately, the only picture without a fish looks a bit disturbing for the fellow at the pointy end

Weight concern is valid, but sounds like your man has plenty of flotation knowledge. How fast do you really need to go with clients aboard?
Bushwacker put a 150 etc on a seafari w/ float-bracket and had to move a lot of things around to correct CG.
I think he touches 50mph and is usually loaded for camping. Not sure but I think the 20s were designed with a 300 lb motor in mind.
I know you didn't ask me, but a new Suzuki 140 or the etec/opti 150 is about as heavy as I'd go

Off topic, can anyone tell me why this thread so wide