So the moral of the mileage story is, stock fuel injected motor and tall gears can gain you almost 100% increase in mileage.

The secret has been revealed.

 

Yep OD and tall gears should definitly get good gas milage. I get 7 mpg with my F250 460 4 brrl Carb C6 3.45 Gears, not to mention that i mess with the Ricers at the lights, and beat them .

Im sure if i get some taller gears and an OD then 15 mpg is possible.
You might want to try out this calculator for calculating RPM at various speeds.
http://www.sjdsm.com/tech/gear_speed.htm

 

You might try upgrading to a 5 speed or add a gearvenders overdrive or both. The problem is high rpm = lower milage. I am suprised you get better milage in town than on the highway. Slowing down on the highway may help. I am thinking you are opening the secondareys on your carb. try ajusting it or seting it up so it dosen't open and see if that helps.
The real secreat to geting 25 to 30 mpg is geting a 18weeler to let you hook up a chain and tow you.
Good luck
Bill

 

LOL!! A few months ago i saw some car tail gating a 18wheeler and he was literally 5-10 feet behind him going about 60 mph! and this wasnt in trafic or anything, this was all open highway. He must of been getting asome good gas milage!

 

For my purposes the secondary adjustment might just be something I need to do. I wanted to run slightly rich for the break in and I do believe my secondaries (replaceable jets on the secondaries) need to be leaned down a bit. I want to hook up to an O2 meter to really tune it closer. I'll give the adjustment or the secondaries a look see though, hadn't considered that. The carb is brand new (Holley 670 Truck Avenger) and has had no tuning other than tweaking the idle and idle screws as well as 2 steps richer on the main jets.

I have read enough to believe the distributor should be recurved, that is coming up soon.

A 5 speed was not within my budget as yet and the T-19 is a stout proven transmission that I appreciate for off roading, I am looking at the 3 speed Atlas transfer case, I can get both high highway gears and low off road gears. Just might serve all my purposes.

I'm not complaining about my mileage, been driving this thing for 14 years now, I have no car payments so paying a little more for gas is within my montly budget easily. I do, however, want to get the max efficiency I can get out of this current set up.

As you can see, it's the fine tuning that I need to do and I'm very inexperienced at it so I may have to part with some cash if I can find a good tuner in CO. (Those are hard to find by sometimes).

I'll also work on a remote operated grapling hook attached to the front of my rig so I can take advantage of that 18 wheeler economy mode of operation.

Jeff

 

leadmic any suggestions cause im running out of things to fix to try and get better gas mileage. A higher OD might help, but thats more money that i'd want to spend right now. -myers

 

build a motor that has a smaller camshaft and intake to help limit fuel consumption. Then turbo it for when you need the extra grunt to get moving. That way you have the fuel sipper (relative term with the 460) that can still give you the extra grunt for when you need it.

 

A good set of headers, a custom tuned chip for fuel milage might help, but if you could go Mass air sequental EFI that would probbly give the most gain in fuel milage. Your truck is speed density EFI and while very reliable they were not the best for fuel milage. The problem would be what the smog requirement in your state is.
Leadmic

 

no smog requirement at all.

so where do we go from here

I thought about a chip, but since it's not OBD-II my choices are limited. Some headers are on the books, but they will probably be resonably cheap summit $100-$300 headers. Already have a Flowmaster exhaust.

Don't know anything about Mass Air sequential.... i'll try to do some research here.

on a side note... wish I had your crew cab!!! for that matter wish I had an old truck... I miss my 73 F-100.

-myers

 

You have two choices for a sequential Mass air set up. You can go with a older mustang ECM that is Mass Air or you can try to sorce the parts for a Calif. or Mass. OBD2 96 or 97 460 they were the only 460s that were Mass Air sequential. The only thing that is diffrent than yours is the ECM, engine wireing harness, and the intake plumimng from the throttle body to the air cleaner cover. The throttle body is the same as your and the air cleaner base is the same as yours. Also the EGR sensor might be diffrent and it will have a extra O2 sensor after the cat all of which can be changed by reflashing the ECM.
The mustang stuff will be easer to sorce, and easy to chip to reprogram to run a 460, and probbly be cheeper. Im not sure what the best year late 80s to early 90 should work the only problem will be running your E4OD Im not sure how to get arround that one, but Im sure their is a way. Their are a lot of sites that can help you with that fordfuelinjection is a good one. Also racesystems is great contact Byron their he can hook you up with everything you need. I would give the whole link but Im sure it would get delited just google the names in red and Im sure it will come up.
Leadmic

 

I have a 92 F350 just like yours except I have a 5 speed and 3.55 gears. It has Thorley triy headers and a K&N fuel injection kit. It gets 13 to 15 regularly as long as I stay below 75mph. Around town it gets about 10.

 

My stock 1995 f250 e40d 3:55 gears that weighs 5500 gets 12 mpg My 1989 f-superduty zf 5 speed 4:56 dana 80 that weighs 9100 lbs get 8 mpg. It was rebuilt with hp535 pistons and the Crane h-260 cam it runs good and pulls like a mule I think weight and gear ratios have more to do with mileage than anything else. Driving habits do account for some differences

 

To me then, if your getting 8mpg with a 9100lbs truck with 4:56's then I should be getting better than that with a truck that weighs.. what high side 8000lbs and 4:10's. But im not...

Thanks for your help guys, i'll keep all this in mind when I get ready to rebuild. -myers

 

I have a 96 F250 extended cab with a 460 engine, 4:10 gears and 4EOD automatic. I can get 14 MPG on open highway driving if I keep it at 50 MPH or less. At normal interstate highway speeds of 65 MPH I will get 10 to 11 MPG. Stop and go driving or fast highway driving makes this thing use a lot more gas. Owned this truck over 10 years now and with 85,000 miles it has only been back to Ford one time and this was for a recall on the speed control. Been a very good towing engine but likes fuel at high speeds.

 

I have a 96 F250 extended cab with a 460 engine, 4:10 gears and 4EOD automatic. I can get 14 MPG on open highway driving if I keep it at 50 MPH or less. At normal interstate highway speeds of 65 MPH I will get 10 to 11 MPG. Stop and go driving or fast highway driving makes this thing use a lot more gas. Owned this truck over 10 years now and with 85,000 miles it has only been back to Ford one time and this was for a recall on the speed control. Been a very good towing engine but likes fuel at high speeds.