I hate to be disagreeable but you're not going to hurt the crankcase at 300 to 350 and heating the crankcase in an oven is preferable to using a torch as it will heat things evenly unless you're one of those folks that does it every day.

Also, the aluminum crank case will expand much faster than the outer bearing races.

Throw it in the oven at 300 for 10 minutes and smack it on a 2x4 and it should pop right out.