78 f250 bad gas mileage
 

i just recently bought a 77 ford f250 2wd 460 with a c6 it has an after market edelbrock 1406 600cfm carb and an edelbrock intake truck runs great but im averaging 4.5 to 5 mpg and about 7 if i *****foot it

That is kinda low. You should be around 8-10 city, 9-12 hwy. Do the usual things. Tune up, air filter, ck air pressure in the tires. What size tires are they? What is the gear ratio? Is your truck loaded down with stuff?

just did a tune up new plugs wires and air filter no change not sure what the gear ratio is its right around 2200rpm at 55 mph 3000rpm at 70mph and it has 265-75r-16 for tires no load on the truck at all and its a 77 not a 78

That does sound low. I would expect at least higher single digits. Can you pull a plug and have a look, maybe post a pic? That's one way to tell if it is running rich.

A related topic - the Edelbrock carb does not usually like the OE fuel pressure - its too high. Does it have a regulator to cut it down to <5 psi? High fuel pressure could push fuel past the needle and cause rich running and poor fuel consumption.

'sounds like 4.11 rear gears to me.

Want better gas mileage? Keep 'er at 60 mph max and drive it like a nun on the street.

I pulled a pug and it seems to be burning fine maybe even a tad lean I'll have to try fuel pressure regulator because it does load up a little on idle I noticed when you go to restart it after it's warm you have to hold it wide open for it to fire and I usually keep it under 55mph

I put a fuel pressure regulator on and set it for 5 pounds and it made absolutely no difference I'm still getting 4 mpg

Did you check the timing? Can't think of anything else.

What's the state of the 460....

worn and tired...fresh rebuild...somewhere in between?

A worn high mileage motor will consume more fuel than a fresh motor.

Nice find. Nothing like old iron! I love it.

Your mileage does not sound too far off. Let's allow some room for possible human error. I am not doubting your mathematical ability but just for conversation sake lets say your are off a little bit. In the case of your platform that might only mean 1-2 mpg but that puts you right around every 460 every made. You are not far off to begin with because 460 and decent mileage do not ever go in the same sentence.

Maybe it isn't you and it is the truck. Meaning the odometer is off a little bit of a percentage and you actually went further than your odom is telling you. This is very easy to happen even if your tire size increased only slightly. If it increased slightly then your odom will read slightly slower than actual.

Test it. Get on the interstate and watch it when passing mile markers. You will know real quick if you keep passing mile markers and your odom has only changed 9 tenths or a little less than 1 full mile.

If you pass and only read 9/10 of a mile then you are 10 percent off. If you pass and read 9 and 1/2 tenths then you are 5 percent off.

Look into that speedo/odom and you might be surprised how far you actually went.

Good luck

P.S.
What is your idle set at? (RPM)
Timing?
I think the tires you are running are a tad bigger than what came with the truck by about 1-1/2 inch. That would cause your error in MPG calculations.

on the last long road trip i took in my truck i got over 12 mpg on highway/traffic driving. truck was a field find that didn't even run when i got it, and fouled 2 sets of plugs trying to get it running again (thats how much unburned fuel and WD-40 had built up on the intake and cylinders). it definitely was unloved for a long time. i'm running a holley 600, and 33s.

his mileage sounds pretty low to me.

12 mpg for a 460 is great. 12 mpg as a whole is not great, decent, or anything there of. It's ashame that gas prices are what they are.

we're lucky gas prices here aren't close to what they are in other places.