318 and 360 gas milage question

[GermzD74]

PEOPLE!...in gas milage wise...would putting in a 360 rather than a 318 be a drastic decrease in gas milage? what about with a 833 trans? i like the idea of something more powerfull than the 318 in my car but ... gas is backign me up a bit...especially since i want it for daily driver...what do you all say?

 

[memike]

I had a 74 flat bed grany four speed and wish I had it today.
318 2bl 24 miles to the gal.
If I was building a street rod for look's sound and gas milage it would be a 318.
you can pick one up to build anywhere and if the day come's that you want more power build it up or just change it out for a 360.
Gas prices are making me rethink my direction too.

 

[edbux]

When I was buying my 01 Ram, there was a difference of a couple mpg's on the stickers between the 318 and the 360. Going into forums, it's more like 4 to 5. I know rel world driving in my Ram, I get 15. If I do nothing but tool around town, it's 11. Long freeway trip netted me around 16.5 We won't even go into the 500 mile trip towing the Dart on a uhaul car trailer, which are very nice trailers. All I will say is that I got to be good friends
with just about every gas station employee from San Francsico to LA.

 

[rumblefish360]

I had a 360 give me 20 mpg's with a upgraded in power with these parts;

Carter 625 AFB on a factory iron intake and a K&N filter inside a '73 , 340 air cleaner.
MSD -6A, viscous fan, dual exhaust off the manifolds @ 2-1/4 with a "H" pipe.

A 904 backed it up and a 8-1/4 rear with 2.76 gears and 235/60/15 (approx. 26 inchs) all around.

The car? A '79 Dodge Magnum. A Cordoba based unit @ 3650 lbs.

For certain, you can do the same in a lighter car and possibly afford a gear change. I would yeild at 3.23's.
More mileage can be found with headers (Coated if possible to reduce heat in the engine compartment.) and a X pipe, a better intake, manual trans for it is a direct drive without converter slipage. Tire size has a small impact on mileage. Smaller items I did not consider useing them would be minimal in mileage gains, but could show something. Like an electric water pump, manual steering, no A/C, skinnier tires, taller tires (are good for the Hwy.) A cooler for the oil, tranny fluids.

On a carb size, if mileage was the goal, a 600 cfm or less carb could still power the engine well. Just do not go changing cams and upping the compression ratio and etc.......
A T-Q carb, if tuneable or a Quadrajet could possibly show some gains while having the abilty for big cfm on wide open throttle.

 

[dgc333]

I get 14-15 mpg in around town driving of my 68 Barracuda with a ~370 HP 360, A833OD and 3.55 gears.
In comparison;
The same car but with a \6 with headers, cam, 4bbl got 18-19 around town and 23 mpg on the hiway.
My 99 Dakota pickup with a 175 HP 3.9l v6 gets 17-18 mpg under the same conditions as the 360. The Dakota has never seen 20 and may get just over 19 on the Hiway.

The Barracuda has not been on a hiway trip of enough length to use a whole tank of gas so I have no hiway numbers.

 

[chrisII]

My 99 Dakota pickup with a 175 HP 3.9l v6 gets 17-18 mpg under the same conditions as the 360. The Dakota has never seen 20 and may get just over 19 on the Hiway.

another good reason for me to keep my 94 dak. it gets 20 to 22 depending on how i drive and how much i drive in town. when they re designed the dakotas and made them bigger they got bulky and heavy. I have to be really heavy on the gas to get mine down to 19.

I agre with whats already ben said, tall gears, manual trans, headders and keep it light

 

[Bakarooda]

My '99 5.2L Dakota returns 11.5mpg combined city/highway. Granted, I just ate a plenum gasket, but I think the most my Magnum has ever returned was just over 13.5 mpg average...

Back on topic, I think both the 360s and 318s can return very reasonable MPG when properly set up to do so.