On a long trip I kept records of exact consumption,usually filling up every 200 miles,one time it was hard to find a open station went 260 miles,tank nearly 11 gallons to fill
The 3000 mile trip average was 23 mpg ,the speed I drove was over 50, many time over 60.
I don’t keep written track of it now, but 5 gallons gets around 100 miles local and parade driving
No overdrive,stock carb and head