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when Consumer Reports would provide gas mileage information ay various speeds ( the practice ended for 1970 and gas mileage was just a range to be expected in normal driving and gas mileage on a 300 mile trip), I recall the 1968 Cadillac Sedan De Ville recorded 7-15 mpg in normal driving but at a steady 30 mph the car actually recorded 18 mpg
The '69 Plymouth Fury recorded 11-21 mpg in normal driving and at a steady 30 or 40 mpg 25.5 mpg
does this mean you could generally add 3-4 mpg to the top number on the upper range at a steady 30 mph??
for example, a 73 Plymouth Valiant with a 225 registered 12-23 mpg in normal driving and 18 mpg on a 300 mile trip
would then my old 71 Duster (essentially the same car) with a 225 get about 26 or 27 mpg at a steady 30 mph?
when Consumer Reports would provide gas mileage information ay various speeds ( the practice ended for 1970 and gas mileage was just a range to be expected in normal driving and gas mileage on a 300 mile trip), I recall the 1968 Cadillac Sedan De Ville recorded 7-15 mpg in normal driving but at a steady 30 mph the car actually recorded 18 mpg
The '69 Plymouth Fury recorded 11-21 mpg in normal driving and at a steady 30 or 40 mpg 25.5 mpg
does this mean you could generally add 3-4 mpg to the top number on the upper range at a steady 30 mph??
for example, a 73 Plymouth Valiant with a 225 registered 12-23 mpg in normal driving and 18 mpg on a 300 mile trip
would then my old 71 Duster (essentially the same car) with a 225 get about 26 or 27 mpg at a steady 30 mph?
In 1976 CR tested the best fuel mileage domestic compacts. The 4dr Maverick was the winner with 26.5mpg at 60 mph on bias ply tires. That was with the 200/3-speed manual. The Plymouth Valiant with the 225 six and Overdrive tranny got 25.5 in overdrive and 23 out of overdrive. The Hornet with the 232 and overdrive got 26 in overdrive and 22.5 out of overdrive. The heavy Nova with 250/3-speed manual got 23.5. All test cars were on base size bias ply tires. I'm sure with modern radials the figures would be .5 to 1 mpg better. At 40 mph Maverick: 32...Valiant: 32 overdrive/26.5 out...Nova: 29...Hornet: 31 overdrive/27 out.
Maybe normal driving includes stop and go. That will kill your gas mileage in a hurry. During the fuel crisis of the 1970's, there was a study saying that on the average, the best MPG was obtained at driving a steady 45mph.
i remember a test of a 73 Grand prix by Cr's with the 455 actually chalked up the best gas mileage of any V8 tested that year
- 8-19 in normal driving and 16 mpg on a 300 mile trip(it was the 16 mpg that earned it the "award")
so at a steady 30 mph that gP was capable of 22-23 mpg
And who cared then when gasoline was in the .20 cents & .30 cents per gallon range.
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