Basically I think most of the traditional ford V8's pre-EFI are capable of 20 mpg, even in 3/4 ton trucks, 4x4's etc - although I wasn't able to get anywhere near it with a 460.

I have done it with the following engines over 15 years.

300 - easy
302 - easy
351W - not as easy
351M - surprisingly easy
400 - never tried
360 Fe - never tried
390 Fe - On the highway easy, maybe not possible in town.
460 - not a chance, although people told me they did.

Of course as shadowviper said (i think) tire size, gear ratios, standard vs. automatic all make a big difference. If you have a 1 ton 4x4 with 4.11's, 35's and a C6, forget it - but you still might squeak out 15mpg!

My highboy has gotten 17 mpg with both a 300 six, and a 351M with standard transmissions, and the 300 got 17 mpg also with an AOD. (i dont really want to go there, lets just say it's not an AOD anymore). That truck weighs 5500lbs, and has a remote transfer case, which adds to drivetrain inefficiency (= less mpg).

Tuning is also very important. People mess with these engines before we get them, and sometimes even though it runs "ok", there are real issues.

I just got my 351M's distributor unstuck today, and finally advanced my initial timing up where it should be, around 10-14* btdc. That allowed me to lean out the carb a bit, and golly did it ever wake the old girl up. I'm expecting an improvement over the 14 mpg i was getting (with stock tires, C6 and crazy high 2.75 rear end) if I stay off the pedal, which of course is much more tempting now to goose.

I think everyone should have a vacuum gauge, and learn to tune from it, as well as monitor things when driving, to get best highway mileage.

 

Yeah I bet it did wake up the 'ol girl going from a 4deg. retard to 14deg. advance!

 

sorry, it wasn't 4* ATDC, it was 4* BTDC, but not enough initial timing regardless.

I still need to port the advance and block off EGR - but I'll get some new mileage data before I bother. Performance is now where I want it, we'll just see if the mileage comes with it.

 

ok not to be a jerk but lets clear this up for everyone who is still confused

ford production motors are as follows

ford mel (mercury Edsel Lincoln) big block, 1958-1968:
383ci
410ci
430ci
462ci
ford fe (ford Edsel) big block, 1958-1976:
gen1:
332ci
352ci
360ci
390ci
gen2:
406ci
410ci
427ci
428ci
ford super-duty truck engine, big-block, 1958-1981:
401ci
477ci
534ci
ford Windsor small-block v8, 1962-2000:
221ci
255ci
260ci
289ci
289ci hi-po
302ci
302 boss
351ci
ford 335/cleveland mediumblock v8 1972-1982:
351ci Cleveland
351ci modified
351ci boss
400ci
ford big block 385 "lima" v8 1968-1997 :
370ci
429ci
460ci
514ci crate

now obviously that is only the ford engines between 1958 and 1980s (with exceptions obviously)

 

you only get 12 mpg with a 400, that sucks
im getting 10-12 in a lifted f150 4x4 with a 460, c6, np205 case and 33" mud brutes, and im having carburator problems, bald tires, and an exhaust leak.

 

I believe you are right on your list. I new most of them but never said anything, it's kinda fun to follow though and see what some come up with. Maybe they will start on how many 6/cy ford made and I can get some more entertainment. Oh , and we are responding to some old post .

 

memorize the list... memorize the list... !!

 

Yes sir. I don't know why some think the 351M/400 is a big block. If it was why can I bolt 302 Windsor heads on it ? I guess maybe because it had a C6 bolt pattern ? But when the 400 debuted in 71 it saw much duty in big LTD wagons that would probably be towing or heavily loaded, so they went with the good old C6. I think there was a few 400 blocks made for FMX tranny patterns, but they are rare.
I have heard rumors Ford made a factory 4 bbl 400 in police cars, but since I've never seen one I kinda doubt it.

 

a 351M/400 is just a modified cleveland. no big blocks in the 335 series...

 

I have a economy guage (same thing) in my 81 351M 4 speed in my F250 and I have done 15-16 with the a/c running, and it's pretty hilly here in Kentucky, so i think 20 is sure possible on level ground. Just my .02

 

i wonder what my 400 can get, after race mods and EFI...?

 

Missed 302 Cleveland in list. Only v8 option we got in Australia 74-77, 78-85 had options of 351 Cleveland as well. So was actually fitted to a 70's F-series.

 

Guess there's 2 schools of thought on that, I always figured the M stood for Moraine Michigan, C for Cleveland Ohio, and W for Windsor Ontario, but what do I know...

 

I was getting 13mpg with a bone stock 351M turning 31in tires. Lost 3mpg when I put in the RV cam and Edelbrock intake....or was it because I couldn't keep my foot out of the secondaries!! (a little of both). With the modded 400 Im still getting 10mpg....uphill....downhill....empty...loaded....d ont matter, its a thirsty ****. Good thing my commute is short and I dont take it on long roadtrips but maybe once a year.

 

my 76 f150 4x4 with 31's, headers, 2brl carb, 360 motor gets a good 8 mpg last i calculated..

but ive tuned it and timed it lately so i'll have to calculate it again.



oh. dont forget to vote in round 6 championship.. vote mine if u like it.