In 1964, before being drafted, my old 1953 Chevrolet used a quart of oil every 30 miles. I simply added a quart every 30 miles or so, even made a 1120 mile round trip that way. It also didn’t especially smoke. Someone said later it was probably main seals.
I came home from Fort Lewis about 10 months after being drafted, and put in a rebuilt engine and transmission, drove that car 2050 miles to Fort Lewis, and drove it a year or two after finishing my two years, then gave it to a brother and bought a new 1967 Chevy II.