Hi, Lazka
I have an 89 b230ft in my 66 122. This car is not running yet. The engine is bolted to the m40 trans(which will probably blow up). This setup has oriented the engine straight up as opposed to the normal slant. I had to use an intake manifold from a b21ft and re position the brake line from the master due to interference. The vertical position of the engine also means I will have to modify the oil pump because I used a b20/b18 oil pan. I also had to fabricate engine mounts. The next problem is the intercooler. The stock volvo intercooler will not fit so you will have to cut the front of the car a bit then make mounts for the intercooler and different radiator.
This is how far I have gotten. I'm not trying to dicourage you, this is just what I have run in to so far. I plan on using LH2.2. Many of the solutions I have come up with for this project have been out of neccesity because I'm broke and don't want custom engine management.
As others have said, a b18/b20 fits and is a great motor. If I could start over, I would consider turbocharging the pushrod motor or buying the John Parker supercharger kit, but I don't have the 5,000 bucks to do it right.
The point is, even a motor that "bolts up" like the b230ft is alot of work, but that's kinda the point. If you get it in there, it will prolly be awesome and you can say you did it.
Good luck,
Dave