So, allowing for the essential differences in size between the two Lockheed airlifters,I'd say that the C-141A had a similar fit to the C-5. Despite that, what made the incident I recall just a bit out of the ordinary was that it emerged that not all crew masks at the time (late 1972) had the same webbing support system, and we had a chap who apparently did not understand how the demand regulator system worked. The net result was an "I Learned about flying from that" occasion from which, fortunately, we all walked away.