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318 guys- you know your fuel mileage ?

pearljam724

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I know these cars aren’t fuel economic vehicles, nor should we care. They are toys now. And there’s some variables on gas mileage,etc. I just calculated my fuel mileage today for the first time to settle my curiosity. It’s a 360 with a mild cam. I didn’t expect to be impressed, but gad damn. 12.5 mpg !!! And that’s no stop and go. Ha ha. I’m curious if guys out there with a 318 have a good estimate what their engine averages ? Also wonder what the manufacturer originally stated what the mpg for a 318 was in 69 ?
 
Currently, 17 highway on my white elephant. Back in the "gas shortage" days I built 318's to get at least 20.
 
In my 66 Satellite, full street trim, 318 poly, 4 barrel 600 Holley, I consistently get 16.7 mpg, in a mixture of fast highway cruising with occasional full throttle to 5,500 rpm and street cruising.
 
I got 18-22 out of my 318 charger 74 that's with a young about 16-17 year old heavy foot .
Man I miss that car
 
My two barrel '72 Satellite 318 (2.71 rear gear) was getting 17 MPG highway last road trip.

Back in '71 my parents new 1971 383 (low compression/regular gasoline) auto Road Runner (3.23 rear gear) was getting 12.5 MPG with mixed driving (mostly highway though). It came with a Holley carb from the factory.
 
Currently, 17 highway on my white elephant. Back in the "gas shortage" days I built 318's to get at least 20.
What did you do back then to improve mileage ? Besides shutting the car off and drifting down hills, lol !
 
My 62 Belvedere, 318 Poly 4bbl gets about 17 mpg on the highway. 3.23 gears and 727 auto. It was rebuilt about 4 years ago.
 
I know these cars aren’t fuel economic vehicles, nor should we care. They are toys now. And there’s some variables on gas mileage,etc. I just calculated my fuel mileage today for the first time to settle my curiosity. It’s a 360 with a mild cam. I didn’t expect to be impressed, but gad damn. 12.5 mpg !!! And that’s no stop and go. Ha ha. I’m curious if guys out there with a 318 have a good estimate what their engine averages ? Also wonder what the manufacturer originally stated what the mpg for a 318 was in 69 ?
I could constantly get 15 to 16 with a little red express 360 in an 82 d150 with 3:54 gears. You must have one heavy foot.
 
I could constantly get 15 to 16 with a little red express 360 in an 82 d150 with 3:54 gears. You must have one heavy foot.
Nope, I averaged 60 mph on a 70 mph interstate. Tach never above 2k rpm. 4 barrel Edlebrock thunderseries carb with a fuel pressure regulator set at 6.5 pounds.
 
True mixed driving stock 73 318 except 2.25 dual exhaust

2.7x rear

14.5 average

I think there's more in it though.
 
that rear gear is what makes all the difference.
odd,but with the 2:79 ratios,you waste more than you would with 3:23-s,
mainly because of the stop n go daily.

im trying to spec out my next project,using a roller 318 magnum,
and im also using a a500 overdrive with a 3:73 ratio.
very interested in this thread and the results from others.
 
Highway driving I could almost get 24 with my 84 Gran Fury. Lock up torque converter no overdrive. I'm sure mixed driving was much lower maybe 17.
That was a low gear.
 
I get 15 mpg when I ripping around town, 20 on highway with my /6 ,10000 miles on the motor now. with 351 rear end and a 700r4 overdrive
twin webers carbs. I just love her , going for a whip today. she purrs @2100 rpm @60 mph
 
Original 318, 2.94 Sure Trak with a RV cam, performer manifold and FiTech in the Coronet. Best ever downhill with a tail wind maybe 16MPG, normally around 13MPG-14MPG so you are not far off. I virtually never have my foot in it either, I just cruise around.
 
My HP 273 and my 318 2 barrel both get 19-20 highway. Both have 3.23's and 27" tires.
 
My 70 Road Runner with a 500 Cubic inch torque monster (675 lb ft of torque) made 16.9 MPG on the highway coming home from the 2023 Power Tour. Our average speed was in the mid 70's, with most of the last couple of hours at 80 MH. I was impressed!

Yes, I have a .7:1 Passion A-855 overdrive, 3.55 ratio rea, which effectively makes my rear like a 2.49 rear ration when in overdrive.

I didn't build this car for fuel efficiency, but I was happy with the mileage!
 
I remember getting 22 mi/ per gal repeatably in a 78 LeBaron, in the city. That was an imperial gallon, and stop start ignition
 
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