JH, seems to be very long and thick and this is mostly evident when women perform oral on him. When he penetrates girls, it's not that impressive. I don't know if it was just that it was the 70s and the angles weren't as adventurous or creative. But whenever I watch his clips, it's always when the girls suck on him that he looks most prodigious.
I will say too, as with most "big" guys, he seems to have the ideal build and frame. I don't think it's a coincidence, that all the big guys are concentration camp thin, with arms and legs like toothpicks -- see Danny D, Vlad, Ramon, Mandingo seems to be short, not so much thin. Anyway, i think his total body physique accentuate his log.