Him and Ike were probably comparable in punch power He objectively doesn't hit as hard as Lewis. Joshua and Vitali are debatable but I lean towards both simply on achievement
Oscar was strong, but powerful is different. Who did he knockout? He decked Frazier a couple of times and Mildenberger four times, but he failed to stop either man. He couldn't even stagger an ancient Patterson. He was tough, though Ellis wallooped him good, and fun to watch, but he is overrated big time.
In terms of just pure power he may or may not be on Ike and Vitali's level. Ike is overrated af, his only noteworthy KO was the much smaller Chris Byrd who started as a damn middleweight in the amateurs. Vitali stoppage rate is so good because he had a good grasp on the basics, good accuracy and timing. Bonavena had none of that. Both of them tended to be arm punchers but Vitalis fundamentals and volume punching make a big difference. Id give all 3 no more than a 7.5/10 in terms of pure punching power. Joshua id give an 8/10 very heavy clubbing shots. Lennox is a 9. Bonavena is nowhere near them in class or finishing ability. Yes theres a difference between power and finishing ability. Bonavena was as strong as a bull but didnt have the coordination, timing, and instinct for stopping a man once he had him hurt.
