1982 Army here...
The PT test score, of a maximum 300, could be attained if the individual did 70 sit ups in a time max. of 2 minutes, did 68 push ups in a time max of 2 minutes, and did a 2 mile run in a time max of 13 minutes.
Whatever got a marine a max score of 500 in 1970, would have to have had max reps for push ups, max reps for sit ups, and a run of x miles in x number of minutes.
Your bro friend needs to owe up to the number of max reps in whatever time frame existed at that time frame.
You don’t forget the criteria.
PS I ran 2 miles in 10:35, during my last PT test, and I was a pack of cigarettes a day smoker, at the time! lol Good times! Ft Bragg. Airborne. Age 25. 1983.
Applauding your fitness back then! Truly impressive to a non-athletic type.
This "online acquaintance" is probably a 15-year-old girl.
Regards,