Did my own digging some years back when I first read (and became obsessed with) that book...and started fantasizing about doing/cobbling together a screenplay for a film adaptation of it (but scuppered unless a big lottery ticket comes my way, because it wouldn't be worth doing it the disservice of trying it on a hack budget with just me and my goon buddies). Alabama Kid is perhaps, I'd submit (blasphemous as it may sound to some ears) a more fascinating and criminally overlooked fighter than Charley & Holman combined.
You won't find it corroborated anywhere (I looked), Heinz never came out and said Memphis = Alabama, but I'm like 99.99% on it. My hunch is that back in the day it was a very nudge/wink, anybody that really knew the game was hip to who the model for the character was...but there isn't a shred of critique or anything published that makes the solid connection. But still, I'm convinced.
Halfway through Thom Jones ,The Pugilist At Rest, which is a collection of short stories with some boxing themes.
I'm in the process of writing the 1st in a boxing series myself. Book 1 will be based around 1860's mixing historical themes with fiction and hopefully give youngfella's a feel of what life was like back then in a subject they will familiarise in boxing, each book is planned to move on up the years to follow on through history. Book 1 will mainly follow an Irish farmer/boxer 1st generation after the great famine who eventually challenges the best in England and later a pugilist who is an ex-Caribbean slave is introduced as the supporting character. It will follow their struggles of poverty, fighting crime and racism and just the plain and simple tough world it was with plenty of scraps . Which brings me to my dilemma I usually write dark and violent crime, dark comedy but I want this to target YA and here is my dilemma I want to target the poor working class in society who don't read much anyway as it is, I didn't either as a teen, but on the other hand very few books target young teens of that background as 99% of authors come from money or stability and what you don't know you can't fake. But if I target YA that means PG, but then it will lose its real street vibe, which is nasty, dark and not all to pleasant like PG, it will feel fake.
I believe the name of the book was called “ The Contender “ by Robert Lipsyte. It was about a kid named Alfred Brooks growing up in New York in the late 60’s and started training at a local gym owned by a famous ( fictional ) trainer.. He initially started training to fend off bullies, had a few amateur fights and then retired. Although I don’t recall him returning to bad habits. He was described as a good kid who worked part time after school at a grocery store and stayed out of trouble.
Robert E. Howard, best known for "Conan the Barbarian," wrote MANY boxing stories: https://en.wikipedia.org/wiki/Robert_E._Howard_bibliography#Boxing_stories