I have a 1970 f250 with a 390 2v and i was wondering what my mpg should be?

 

Most get 10 or less, you might tweak it and get 11-12 but that is usually about the limit. With overdrive more is possible.

We have opened the window at the liers camp, you can hear numbers all over the place. Most higher numbers than the ones I posted are the result of mis-matched speedo gears giving false readings.

Gonna sit back and watch the



John

 

with a 390 C6 i would have to imagine you can have the ability to get 18 mpg.

when i was driving my 40 year old 360 from seattle to orlando i was getting an average of 13. this was documented with my friends gps unit several times along the 3300 mile trip. nowadays with a few more special dave tweaks and tuning on it now gets 15.8 mpg with an empty bed and the a/c not running which was documented on my way up to new jersey from orlando for the 3rd time. im laughin all the way to the gas station all the time! cause this is not much less than the newer trucks. my dads new f150 gets 18.
with a/c running i get mid 13's. it blows ice cold but the compressor still has some issues and puts strain on the motor. plus the mpgs vary depending on how hot it is, how windy it is, and how fast i'm going.

if you do:
fresh wheel bearings, fresh ujoints, high performance ignition, good fine tuned dead on ***** accurate carburetor, fresh timing chain and gears, new aired up tires, and an electric fan i can guarantee you there will be an increase in fuel economy. but then again this stuff all costs a tremendous amount of money when added up which can buy you a freakin swimming pool filled with gasoline. same goes with the overdrive units.

but i'll bet you if i had a manual transmission and a freshly rebuilt 390 i would be pushing over 20mpg

but yeah 10mpg seems to be about what most people are getting from alot of the threads ive read

 

I know with My 72 running a Marine 427, 4bbl carb. C6 with a shift kit, I get about 6mpg. No high mileage, But not so bad for all the cubes.

 

OMG!

 

Can I sit with you john ? I think it may get deep . LOL

 

I get about 7 to 8 on the freeway at 65 MPH. If i keep to side roads and under 45 i can squeek about 13 to 14 out of the 360.

Garbz

 

My old '73 F250 with a four barrel 390, np435 and 4.56's only got ten miles per gallon.

 

when i was driving my crew cab long bed F350 up and down the Cali coast i maxed my 460 C6 3.73 out at 11MPG it was not stoping at all running both tanks and driving at 55 to 60 mph, but most of the time i get under 10.

 

My speedo's not connected,but the gas gauge works,and it doesnt seem like much time elapses between fillups.....Of course,the height of a highboy,extra wind resistance,extra weight,and plain ole friction from more gear turning compared to a 2wd cant help.....9-12 mpg are the numbers ive heard,and believe!

 

wonder how i can be able to prove this online

 

I get 8-11 with the 460 full time 4x4 f150 . the old 2x 76 f250 390 4speed, 3.73 geared California truck got 10 city 13 highway. would have been a flat 10 with 4.11's for sure. 70 bronco with 351 c6 and 33's got 10/13
pontiac 400's get 18mpg on the highway can't see why a 390 with the right cam wouldn't

 

my truck is my daily driver everday to and from work which is 45 miles away and its all highway. and i also use it for everything else and have been for the last 3 years. i drive it everyfreakinwhere. i just cant make this stuff up. i just dont think there is any way over the internet to prove what your gas mileage is without freakin video taping yourself or something.

 

Dave, You may get 15MPG, Its not impossible. Just very hard to get the right combo to do it on these older truck, Please why not share a full break down of what your running to achieve this. Solid number always help.

 

new timing chain and gears. edelbrock perfrormer cam. edelbrock performer intake. edelbrock performer 600 cfm 4 barrel carb. phenolic spacer underneath. another phenolic spacer above inbetween it and the air cleaner. edelbrock hydraulic lifters. performance distributors dui hei ignition with wires. hooker competition headers with cheap cherry bombs. fresh tires. fresh wheel bearings inner and outer. fresh kingpins. fresh ragjoint. fresh draglink. fresh power steering pump. fresh alternator and voltage regulator. fan shroud with stock fan. fresh ujoints on output shaft and driveshaft. fresh shocks. and whatever i might of missed. all components perfectly tuned and operating in synchronicity with each other, spent lots of sleepless nights and many cans of beer. motor is original 40 years old and passes compression test with flying colors. 60k on the odometer and i honestly dont think its 160 or 260. bought it off an old man down the street for 400 bucks bone stock and just went nuts with it.