Anything will fit if you have the time and them money. 
I'd guess that it wouldn't be too hard seeing how people can haven't had
too much trouble getting them into 1800s. Although, I'm curious. Why
the B200 and not the B21 or B23 variants? Same size block and head if
I'm not mistaken. The problem areas will be the break booster and
intake manifold, exhaust (sep, turbo) with the upper a-arm and possibly
oilpan and crossmember (and potentially the hood.) In the case of the
1800 some people put the b21/23 in upright and used the b20's oil pan -
others have had to cut at the body/cross member to put it in at a slant.
Don't know about the transmission.
-K
