My Mothers Cousin had
a 58 Super they replaced it with a 66 Ninety Eight Luxury Sedan that was driven daily up into the early 90s, one of the most comfortable cars I ever rode in, got great mileage too for a biggg car, 20 on a long trip..it was always a joke, Her brother in law, who was the service manager for the local Olds dealer had a 68 Ninety Eight, it never got over 14 mpg...they went to the beach every year, the 66 would go all the way to Myrtle Beach, drive around down there all week and wouldn't have to fill up until they started home, the 68 would have to stop on the way down for gas!!LOL Both had 26 gallon tanks I think.