I think most of us are aware that Pryor beat Hearns as an amateur at 132. Hearns was very young and inexperienced. He also didn't have the muscle that he had later at WW. At 147, I think Hearns wins, So how about meeting in the middle, at 140? Hearns often said that making weight at 145 was never a problem, so 5 lbs less isn't much of a stretch
Pryor stops a weak Hearns at that weight, Hearns may have said he had not trouble getting to 145lbs, but to me, it’s clear he was more vulnerable and weak at 147lbs than 154lbs. People don’t realise they should put on weight until they do, they don’t know they’re weak at a weight because they can’t compare it to how they feel at a higher weight because they haven’t yet been at that higher weight.
A prime Hearns would be beyond drained at 140lbs. The last version of Hearns that could have safely made 140lbs would have been a teenager. I wouldn't favour either vs a prime Pryor. At 147lbs and above, prime for prime, Hearns destroys Pryor.
I don’t think that Hearns could have functioned well at 140 lbs once he had reached the pros and was in his 20’s.
It would have been a great fight, very entertaining. Hearns' reach, jab and speed would have allowed him to win many rounds before Pryor's aggression, stamina and high workrate would have managed to change the course of the fight. I say Pryor by tko after the 12th round.
Hearns was a bigger and better fighter, but getting down that low might have been too much for his body at that stage. He might be a zombie at 140, and then would get taken apart in ugly fashion.