Yeah, It's a completely different motor. It's a worthless peice of sh!t that can't swap into anything but another prelude. Th block you want is a b20b (97-99 CRV) or a b20z (00-01 CRV). The b20z has higher compression (8.5:1 I think) but most people get new pistons neway, for all motor applications at least.
I don't know about the 88-91 Prelude B20A blocks being peices of shit, I read some where in an article that a person from spoon said the worst block to do a V-Tec head conversion on was the B20B from the CRV's, due to some sort of problem with the bottom end, it doesnt mean they don't work, but i'm just sayin for the sake that the B20A is not as bad a motor as u say, as for the prelude motor with a B16A head it has been done and it made the same tourque as a stock b16a motor, but with a dead cylinder, so imagine what it would have done it it had all 4 working correctly, the original site that did the B20A/Vtec was www.ludespeed.com but unfortunaly he does not have the site up at the moment, when it comes back online you can read the outcome of the lude-tec motor. By the way, this is also something i was going to do when I had my 88 Prelude.
whta i meant about it being a peice of shit was that the b20a wont swap into any other car. the b20vtec is probably the best swap to do showin a possible 220 horse. The bottom end problem your talkin about is thin cylinder walls, a problem common to all bseries motors. Its not that big of a deal If you tune right and use quality parts and it can easily be dealt with be getting it resleeved or using a block guard.
You don't have to even sleeve the engine to make it run well. For NA the B20B is a great bottom end for a VTEC head swap. We have a thread on it in our FAQ, lots of info. Or you can ask Calesta he is running a B20VTEC in his Civic and is the local authority on that build.