Engine Block replaclment?

I got this 92 735i at an towing company for connecting 5 PC's tos file server for them,($400.). I went to put oil in it yesterday and noticed it was coming back out. SO grabed a flashlight and there is a small, 2" crack in the front of the oil pan, right behind the cooling fins. So I tried turnung the motor over by hand and no go. I need to know which block will interchange with this one. I do have a 87 525i thst has been wrecked but ran fine, would it work or what should I DO?

Suggest you join www.roadfly.org and ask on the E32 board. My GUESS is that the 525i engine would not fit without modification of the motor mounts, etc. Also, car would be underpowered. The '92 7-series BMWs also came with a V8 (740i/iL) and a V12 (750iL), but they had different transmissions as well.