Stanley Ketchel vs Jack Johnson comes to mind
Also Henry armstrong at welter and middle, pac man at welter, qwai at cruseiweight and havyweight, any one else?
Nikolay Valuev, 7ft tall, 333 lbs vs Clifford Etienne 6"2 tall, 217 lbs.
Imagine facing a guy nearly a foot taller than you, and over 100 lbs heavier. No wonder he frigging retired after.
5'5-5'6 Qawi against 6'4 Foreman was ridiculous.
Armstrong was smaller than his opponents but he was usually stronger.
Henry ArmstrongUploaded by TheGreatA
Jimmy Wilde was outweighed by many of his opponents.
Jimmy McLarnin started his career at 120 lbs, winning a decision over Pancho Villa, and ended it by KO'ing highly regarded WW champion Young Corbett in one round and having a trilogy of fights against WW great Barney Ross.