[Mark]

If you've raised the stringers/floor, you may be able to pull it off. However, if the floor is at the original height, whoever told you that 466#s on the transom would be fine with the scuppers grossly mislead you. The 200hp isn't the sticking point here, it's the notion of the four hundred and sixty six pounds. If you want lots of ponies back there, get a lighter 200hp. Those old Mercury's were pretty light...

I currently have a 416# engine on a SeaCraft 20' that the floor was raised 2.5" in and I wouldn't want that floor even 1/4" lower with that weight back there.

Either raise the floor or look for the lightest engine you can find. I'm not saying this because I have anything against the engine you are considering, I just know from past experience with my SC18' that 466# is simply too much weight if the boat is in the original configuration. I didn't raise the floor in my 20' because I had extra coinage rattling around, they NEED it with heavy engines....and my engine is 50# lighter than what you are proposing.

Go to a dive shop and rent 466# of lead weights (really, give it a try). Now, park that boat next to your dock and load that weight right next to the transom and see how your scuppers are doing.