Stallone has relatively narrow clavicles. Great physique, even now, but I doubt he could have been truly competetive.
Tyson for sure. Brutal shoulders.
Wahlberg has a great natural physique.
Mickey Rourke is a meat axe. Check him out in the remake of Get Carter.
Nathan Friend, plays for the Gold Coast Titans, great physique.
Ben Johnson the sprinter.
There's a cleaner / wardy at my work. Dude's about 5'4'' and early 40's. Seriously could still be a contender. Dude has genetics out his arse but doesn't train and has a gut.