He'd probably defend against Ali himself. Ali would surely call for a rematch, and Shavers wouldn't have refused that because of the sheer amount of money he'd make. At that time, fighting Ali, even when he was past his prime, meant fame and a lot of money. It was an opportunity of a lifetime so some of Ali's opponents didn't care if they lost.

At this time it was common to have rematches which is why the belts stayed with a few fighters and others never got a chance.

If Ali lost then won the rematch there would probably be a third fight, so another contender would not get a fight for more than a year.

It would have been an Ali rematch -- there would have been contract language that made it mandatory. It was a close fight, but opponents of The Greatest knew that they needed to notch a huge scoring advantage to gain a decision; it can be argued that Norton captured the bouts at The Forum and in Yankee Stadium

I just watched the fight on youtube and man that was definitely one of the most entertaining fights ive ever seen. Shavers hits like a truck going at 100mph. I literally don't know how Ali took his hardest punches but I think Ali deserved this win. Shavers legs at the end started to quiver and I think if they didn't stop the fight he would eventually fall. I always knew Ali had endurance and speed but I didn't know he could take hits like that. This is just my opinion im no boxing expert

his first defense?

Just saw the Shavers-Ali fight, and felt that Shavers was robbed( he should have gotten the decision by 8-6-1). If he was rightfully given the decision, who would have been his first defense? Muhammad Ali? Ken Norton? Jimmy Young?