I killed 1 bear with a 52lb Black Widow, 2213 arrow and 160 grain Snuffer (525 grain arrow)-through the chest, breaking 2 ribs, and into the dirt on the other side. 2 bears with 55lb Widow, cedar arrows and big Snuffers (580 gr arrows), both passthroughs with the second entering the chest, getting both lungs and heart quartering away, and exiting through the front leg to stick in a log. The last 2 bears are P&Y size. Black bears are thin skinned/light boned compared to a deer except for the shoulder which is heavy. If I were you I'd try a 2213 from your bow and get a good, solid heavy broadhead. I'm partial to Snuffers, of course, but if you want a 2 blade I would highly recommend the 160 gr STOS, it is a fine, tough head.
Ryan