The aluminum expands more that steel. Even if everything is the same temp the bearings SHOULD come out. Now with that said, getting the crankcase as hot and quickly as possiable is best. i use a propane torch. Put the crankcase in the antifreeze, bearings and all and get everything as clean as possiable. It sounds like you will be replacing them anyway. That should help with removal by getting all the old crud out of the way. The antifreeze won't hurt the bearings, so if they are bad it's because they were bad before you cooked the motor.

ken