In 1971 while stationed at Minot,I owned a 1966 polara 383 hardtop,barely 5 years old. got it with 40k on the car. travelling around base to base I saw 17-18 at 65mph, and 12 city driving,
I have one today as well, as the same 383 gets 12 city with crap gas, and maybe 15-16 highway. But in 1971...