I grew up with a friend who was just like that. 6'2" and barely 150 pounds soaking wet. But he was always down to scrap if someone challenged him. Just had zero fear. He would crank up Pantera in his car on his way to a fight with someone. He could really throw hands and once he was on top of you, it was an elbow and forearm parade to the head and then you were out.
leverage, technique and street fighting experience go a long way when it comes to subduing a larger opponent. Precision beats power and timing beats speed. The toughest guys I always saw fight were usually guys built like Abe Lincoln. Tall with a long reach and scrappy as hell. Would fight until they were burger. Not a lot of muscle and size but they didn't gas quickly like most meat heads do.
Sounds like my buddy. He had zero fear, which means a lot in a fight.
Kind of sad, but his dad committed suicide when my friend was young. On father's day my friend would drive around trying to start fights with people just to take out some aggression.
These are the people you don't want to fight; he wanted to truly hurt people.
Street fighting is a different animal, i've seen some guys get their asses kicked who looked like real winners. You can't discount a guy who can get off 3 punches before the other guy knows what happened. It's over so quickly. No ref, no gloves, most of the time alcohol is involved.