Vasiliy Lomachinko had 396 amateur fights before turning pro. He lost only 1 of those fights by decision. He went on to be Featherweight and Lightweight champion
Wow... someone who actually tried to answer the question! Robinson is a good answer - but not the right one.
Figured someone out there had a longer one but Ray’s a good starting point to the discussion. We have a benchmark now and no one need guess someone with fewer than Ray.
Yep, you got it! Quite a few world champs beat Robinson's 136 - but no one tops Levinsky's 206, before he ran into Dempsey!
I barked up the Willie Pep tree and it seems he was first KO’d by Saddler in his 137th fight - the same number of fights as Ray Robinson when he rtd v Maxim. An interesting co-incidence but not the right answer.