Mainer,
Sorry to hear about your engine. Here is a link to the thread where you'll find some step by step pics of when I removed my Sea Drive to install bracket and OB. Hope it helps...
http://www.wellcraftv20.com/cgi-bin/...02890;start=15
I'm not sure how she will sit in the water since I put a 200 on her with a non-flotation bracket. We'll see soon enough. However, keep in mind that the Sea Drive is non-flotation as well. I think when I ran the numbers the Sea Drive was comparable to the weight of the bracket and OB (though the latter was just a bit heavier). The biggest difference is that the motor hangs off the transom further back, which will certainly affect the weight distribution as Willy has pointed out...