68 390 gas mileage
 

guys i need help ,i just purchased a 58 f-100 stepside with a 390 c-6 3.00 rear gears. i wanna replace the intake with a good performer rpm and a new carb but i also have a 91 thunderbird 5.0 and aod i have thought about replacing the 390 with ,i want a truck with good power but i wanna be able to drive without stopping at every gas station HOW bad will the 390 be on gas with this set up .

8 to 10 mpg in most driving. 15 mpg if you run on flat ground no wind at 50 mph.

15 mpg on my 1974 f-100 , 390 4V , manual , 3,5 in rear , crane RV cam .
www.fartssperre.no

thanx guys for the numbers but what size and brand carb do u run