Louis would beat Ali

Ali was a very talented fighter but technically he was pretty bad.
Ali leaning back from punches would be suicide against Louis, since ww2 the art of feinting has been practically lost (especially at HW).
Louis would probably feint and Ali would take the punches, Ali once up close his reflexes would be just a fraction of what it was on the outside, he also seemed to be blind to left hooks.
Louis is technically too good for Ali, I don't think any version of 60s Ali would get a majority in 3 fights against Louis.

Louis his chin was not the best ever, but Ali isn't the strongest puncher.
I just don't see it for Ali here.

Louis was talented enough and would be technically a few classes above Ali.

 

Louis could punch as hard as both Cooper and frazier who both knocked Ali down.
He was faster, Ali's leaning back would be suicide against Louis his right hand.

Louis is also a much better finisher than frazier and Louis is a much more dangerous puncher than frazier.
As I said, once a fighter got close, Ali his defence would be gone pretty quickly.

Chuvalo having a great chin was pretty limited and already gave Ali enough to hurt his ribs for weeks and give him bloody kidneys.

Louis would be unlike any fighter he ever faced.

 

Louis would pressure Ali, like Frazier and Norton. Ali didn’t like pressure, as he preferred to box from the outside. Joe Louis once described how he would have fought Ali, The Ring, Feb. 1967:

“The kid has speed and there’s no one around to outbox him, and the opponent who tries is in his grave. Especially in the middle if the ring. I’d see to it that Clay didn’t stay in ring center. No. He’d be hit into those ropes as near a corner as I could get him. If he stayed on the ropes he would get hurt. Sooner or later he’d try to bounce off, when he did he would get hurt more. I’d press him, cut down his speed, and bang him around the ribs. I’d punish the body. “Kill the body and the head will die”, Chappie use to tell me. It figures. Sooner or later he’d forget about that face of his and he would start dropping that left hand like he did against Mildenberger and Chuvalo. Those fellows got their openings by accident, and fouled it up. I would work for it and wouldn’t reckon to miss when it arrived. Cassius Clay is a nice boy and a smart fighter. But I am sure Joe Louis would have licked him.”

 

"Louis punches were not just heavy punches like Foreman or Shavers but fast and explosive punches. Ray Arcel, one of the greatest trainers in history worked against Louis in 14 of his fights, said, (Anderson, 120), "Louis once drove Paulino Uzcudin's teeth right through his mouthpiece!" Arcel said it was the hardest punch he ever saw. Not Joe Frazier, not George Foreman, not Earnie Shavers had that kind of dynamite behind their punches.

Louis would catch Ali along the ropes with one of his most powerful and deadly hooks. Unlike Frazier, Joe Louis could throw a triple left hook with speed and power as he did against Max Baer. Ali’s legs would turn to jelly. Louis combinations would fire with piston like precision and the power of a human jackhammer. The speed of Louis assault would be mesmerizing. Ali would be battered unmercilessly and unceasingly until the referee was forced to call an end to the execution.

Some "analysts" never bother to study films and therefore don't see the technical flaws in Ali's style demonstrated in this article. Instead they make a pointless argument as to how well some of Louis opponents would have done against Ali or the quality of Ali's opposition as compared to Louis. It doesn't matter. Styles make fights. Billy Conn and Max Schmeling did not have Joe Louis physical attributes or his style. Ken Norton had the style to give Ali fits; a right parrying hand to block Ali's jab-a good left jab in return, pressure on the inside, a strong body attack and a good left hook that Ali was susceptible to. Joe Louis had all these attributes and was a faster and far more powerful and explosive puncher than Ken Norton was.

Joe Louis was not well prepared for some of his opponents because he didn't know much about them, but any fighter that gave Louis trouble the first time was destroyed in rematches. Louis was 10-0 in return engagements. Louis proved he could make the adjustments to defeat the weaknesses in an opponents style. Ali, despite all his innovativeness, never did understand why Norton gave him so much trouble. It was because Ali didn't know how to block a jab and Norton's trainer Eddie Futch knew how to exploit it. Eddie always believed that Louis had the style to beat Ali. In the March 1992 Ring, Futch picked Louis to stop Ali late in a mythical dream fight. I never understood why until I quit repeating the same old lame arguments and started really studying films. Joe Louis had the style to exploit Ali's technical flaws.

In comparison to my original somewhat superficial thoughts from my 1991 letter a more thorough examination of the facts shows the following to be true:

While Ali is the fastest heavyweight ever, Louis was nearly as fast with his hands. Ali’s many tactical mistakes would leave him open to one of Louis lightning-like strikes. His foot-speed and jab would be negated by Louis properly placed right parrying hand. Louis would render ineffective Ali’s primary weapon, his left jab, and drive him to the ropes vis-a-vis Ken Norton.

Ali was a master of strategy against slow handed bruisers like Liston, Terrell, Foreman, and Shavers. He had more trouble with men with hand speed who could punch with him like Doug Jones, Norton, and Jimmy Young. Louis was superior in hand speed to any of these men. With the previously outlined strategy, which Blackburn and Joe would be sure to implement, Louis would not be at a strategic disadvantage against Ali.

Ali had a great chin, but he was not a diety. Nat Fleischer rated Joe Louis as the greatest finisher in ring history. Consider that Joe Frazier had Ali in serious trouble and he did not have Louis speed of delivery, combination punching ability, nor was he as deadly a finisher. Had it been Joe Louis he would have kayoed Ali in the first Frazier first fight, and also in the third. Liston, Foreman and Shavers were big punchers but slow of hand, and could not carry on a sustained assault for 15 rounds. Louis definitely would not tire and he was a more explosive and sharper puncher in the mold of a young Mike Tyson. Louis had real shock value in his punches. Ali’s chin would have its greatest test not against Frazier or Foreman but against Joe Louis.

Ali was never beaten until a 3-year lay-off, but it was still close to his physical prime he was less than 2 months removed from his 29th birthday. Some would say he lost to Doug Jones, and he was nearly kayoed by Cooper so his unbeaten streak is not without tarnish. In comparing Ali when he retired at age 36 after beating Spinks his record was 56-3 with 37 kayos. Louis when he retired as champion at age 35 was 60-1 with 51 kayos. Louis also lost four of his best years due to WW2 just as Ali lost 3 ½ years in his forced exile. Overall Ali faced the better competition, but Max Schmeling (a first rate counter-puncher), Max Baer (one of the hardest hitters in division history), Arturo Godoy (never knocked off his feet in his first 70 pro fights), and Jersey Joe Walcott (one of the slickest boxer-punchers of all time) are better than anyone that Ali faced during his prime years, with the exception of Sonny Liston. Both Ali and Louis were dominant champions."

 

Would prove suicidal

 

Both Cooper and frazier proved Ali was vulnerable.
Louis could punch just as hard, was more dangerous at delivery and was a much better finisher.

 

But frazier did beat Ali.