I bought my 2+2 Catalina Conv.new in 1965.It has 10312 miles on it.Completly orginal but Tires,Exhaust and Battery,411 rear gears and if you noticed there are no side mirrors on it.One funny thing is two days after it came in I had to replace the cam an lifters, which I did my self in the dealer work shop. I would not let anyone touch it.
It has never been in any rain or snow.It is always been in a heated garage. I will be 75 years old in July. I also have a 1979 Trans Am,1991 ZR1 Vett, an 1993 GMC Typhoon

Another original owner - I think that makes seven now. You obviously have a talent for checking off the right boxes on an order form. Convertible, HO motor, 4-speed - hmm, hmm, hmm.
You bring up an excellent question. Who else out there can top 75 years of age? I don't think you are the oldest (I've got a couple of guys in mind, but I'll let them speak for themselves). I do, however, think you have a good chance of being the oldest original owner. My friend and neighbor Big Red bought his '65 coupe new, but he is only turning 71 in April.

Who wants to claim the senior's title?