Fuel economy help!

[osomxl]

I recently picked up an 86 F250 extended cab and thought it had a 351w in it and have now discovered that it in fact has the 460 big block.

that thread can be seen here need help identifying my motor!

I drove it out to the desert and back and calculated it at 5.2 mpg!

Can somebody tell me a little more about this motor as in stock form from Ford such as HP, TQ est. fuel economy?

I have the Haynes manual, but it doesnt go into detail enough to know what goes where as far as vacuum hoses and sensors and smog equipment.

I need your advice as how to maximize fuel economy.

What size type of carb rebuild kits are available and what jet sizes?

What spark plugs should be run?

What weight oil?

What else can I do?

Where can I find diagrams for all of the sytems and components so I can replace hoses and sensors as needed?

If I could squeeze 10 mpg out of this puppy I would be ecstatic!

-Eric

[331sbf]

Ah let me see, you are asking about Fuel economy in the same breath as 460 and F250?????????

Helpful bit,
1) Aerodynamics, is your bed covered or open
2) rolling efficiency, R you running road radials with proper airpressure, or mud pluggers?
3) F250, is 4x4 right, Free wheeling front hubs?
4) Check vacume advance is working and timing set properly

Good luck

[osomxl]

331sbf,

I have an open bed at the moment and it will probably stay that way as I am an electrician and also do some construction.

I am running road radials, General Grabber TR's to be specific and I am running the correct pressure, 50 psi front/80 psi rear.

I have regular 2wd thankfully!

I will be checking the vacuum and timing, but I also need to find an online resource that will show where all those darned hoses go and what they are connected to.

[mgr409]

Eric

Shift out of 1st gear!

Seriously, even an F250 should get better than 5.2 mpg. There is an issue with the motor such as vacuum leak, ignition trouble, spark plugs missing, ect. Give it a basic health check and I bet you will find one or more basic things.

Mike

[Mike Forte]

Hi Eric,
Your 460 is the last of the Holley Carbed engines. I have an 86 E-350 Cube Van 460 Ford that i put a BMW 2002 into it and towed a 24 ft trailer loaded with my Z-28 and lots of spares. It would get about 10-11 mpg or 7 mpg towing hard.
Your carb needs a good refreshing or replacement. Keep in mind that hoses at this age are needing replacement
I have the correct carb available if you need one.

Originally Posted by osomxl

I recently picked up an 86 F250 extended cab and thought it had a 351w in it and have now discovered that it in fact has the 460 big block.

that thread can be seen here need help identifying my motor!

I drove it out to the desert and back and calculated it at 5.2 mpg!

Can somebody tell me a little more about this motor as in stock form from Ford such as HP, TQ est. fuel economy?

I have the Haynes manual, but it doesnt go into detail enough to know what goes where as far as vacuum hoses and sensors and smog equipment.

I need your advice as how to maximize fuel economy.

What size type of carb rebuild kits are available and what jet sizes?

What spark plugs should be run?

What weight oil?

What else can I do?

Where can I find diagrams for all of the sytems and components so I can replace hoses and sensors as needed?

If I could squeeze 10 mpg out of this puppy I would be ecstatic!

-Eric

[osomxl]

Thanks for the replies.

Mike, how much does a rebuild kit run these days, and where can I find diagrams for the vacuum and smog systems?

After 25 years, the engine bay has spliced hoses and stuff added and deleted. I need to go through and replace hoses and make sure they are going where the need to be, but need some type of diagram to go off of.

I want to start replacing all the hoses and filters and vacuum lines and plugs and after I am sure that they are hooked up correctly I can then go through the tune up process and get things up to factory par.

I would be absolutely thrilled if I could get 10 mpg!

[JKleiner]

Originally Posted by osomxl

I would be absolutely thrilled if I could get 10 mpg!

I remember the original buyers af 460 equipped F250s saying that exact thing in 1976!

Jeff

[osomxl]

I have read on several other forums that 10-12mpg is achievable by re-jetting.

Now if I can only find the schematics for the smog and vacuum systems so I can start on the tune up!

[Mike Forte]

Hi osomxl,
A rebuild kit typically sells for $35.00 or so. You should get the Holley carb number to insure the proper kit.

[Qwik 1]

I recently bought a 1991 F350 crew cab dually (with 8" bed...it's long) 2wd
460 auto fuel injected. It gets 10mpg. 12 on the highway @60mph
Towing about 7mpg with a 5th wheel 26' enclosed trailer.

I can't complain. I'm guessing the fuel injection has a big part in it.

Brian

[LAZER2KGT]

what rear gear do you have? My dad has a 86 F 250, 460 4 sp, 4.10, 2wd, gets around 8 MPG if he's lucky, 6 with a camper and pulling a ranger 4X4. If you drive much over 55 with 4.10 gears and no overdrive, it will suck the gas fast. Everything is stock except he put daul exhaust.

Mine is a 86 F 250 4X4, 460, 3.55 gears, 4 speed. I get 10 no problem. I stripped of all the smog crap, have headers (removed the twin air pumps), daul ex., performer intake with a 750 eld carb that I played around jetting it.. MSD ign, recurved dist. The 3.55 gears are a bit tall for me at times, but for just driving around and not pulling anything they are great... I use 30W oil, jacobs plug wires, time it around 12 to 14 deg btdc (sometimes ppings a bit, so I run mid grade gas). I also replaced the timing chain and advanced the cam 4 deg, as the stock chain retards the cam for emissions...

Scott

[osomxl]

Well I changed the plugs, wires, cap, rotor.

Rebuilt the carb for 50 bucks and almost burned it to the ground when the floats stuck open and kept pouring gas into the carb and it backfired up through the carb.
Luckily I had an extinguisher in my ranger close by and had to empty all of the 2.5 lb. bottle on top of the carb and down the back towards the tranny before it went out. I tore it all back apart and had to clean all the dry chemical from all the nooks and crannies (MAN, that stuff sticks to everything!).

Got it all put back together and she fired right up. After a few minutes to burn off all the sludge on the pistons from running so rich for who knows how long, she now runs like a raped ape!

I went through the process of setting curb idle and fast idle, but apparently the harmonic balancer is shot and I could not verify timing.

Skip to today and took her in to get smogged or at least get a clue of where she sits at and she passed with flying colors, except that since the mechanic couldnt verify the timing he had to fail it. What a waste of $55.00.

So I am now looking for a cheap balancer and will swap it out next week and pay to have it done again so I can be legal!

I calculated the other week that I was getting about 10.6 MPG.