Had above average lung volume for his height. He boasted of near a world record. Mike can do the same trick that Paul did with his chest expansion but it is still mostly a trick.
It says in his short bio in my book that his lung volume increased from 180 cubic inches to 436, at that time close to the world record. This is 3 liters to 7 liters.
He might have been referring to lung volume versus height as a 7'6" inch tall person can have in excess of 8 liters maybe more.
Height has a huge relevance here so just what world record did he get close to? For midgets, his height, giants etc.