My `92 F250 with a lift kit and 35" tires, 3.92 gears, 460 with straight-pipe exhaust, K&N filter, and a 200lb front bumper gets 12.5 mpg in the summer without the topper on. Right now, I get 10 mpg.

I also used to own a `69 Torino GT fastback with a 351W I rebuilt. I ran a mild combo since it was both my cruise car and my daily driver. With a 3.00:1 rear, I got 21 mpg on the highway.
My `70 Torino GT with a stock 351C 4bbl and the same tall gears got only around 16 mpg.
My 450 hp `65 GTO with 4.11 gears was the worst vehicle I've ever owned for gas mileage, it got 6 mpg on the highway .

 

>>I guess I really don't know for sure what specs he used, but
>>I assumed he used these specs. He may have read something
>>different. Do the shops in your area think these are too
>>big or would they go bigger. I've not seemed to have any
>>problems thus far aside from the formentioned need to run 89
>>octane.
>>
>>Tony
>
>Glad you asked, I'm getting so frustrated with this whole
>deal. All these guys in town would go smaller!!! The guy
>that bored my block, said he would go .022 top ring MAX! KB
>recommends .029 MIN! Everybody else in town recommends .016
>- .018 and one guy said he would send rings back if they
>measured close to .029 out of the box and runs KB's almost
>exclusively. Most guys here think I should follow KB, but I
>would really like to know why/how these guy get away with
>small gaps?
>
>you can read my post here
>https://www.ford-trucks.com/dcforum/DCForumID11/1628.html
>
>Since then, I make it a habit to ask whoever has them.
>Any advice is appreciated.

I think the only advice that I could give would be for YOU to call KB directly and talk over your concerns with them and try to get some reassurance about ring end gap. They'll probably say something like..... we won't warranty any piston failure if our ring end gaps aren't followed..... but you might get some further details about why they want the larger gaps.

However, think about it. The difference between .017 and .030 is 13/1000 of an inch or just a little over 1/100th. Is there going to be much compression or performance lost by going that much bigger. I'd think that the greater damage and 'loss' would be by having the rings too tight, and having a thermostat stick or an engine start running lean and hot. Or maybe KB recommends these gaps to cover their butts against the guys who never check their radiator water... AND/OR who run higher compression and hotter sparks with wrong timing and other problems.

Again, I think it would be reassuring and good for you to call KB DIRECTLY and talk with one of their service or tech people.
Good luck
Tony

 

Not sure how you guys are getting 18 MPG, I have a E-250 quad van with a 460, I'm lucky if I can get 3 MPG. I'm in procces of trying to figure out the vac lines, it runs like *****. If any one might know how to fix vac lines let know, it would be most helpful
Tim

 

thx for the input Idaho(I am almost ID-- Spokane, WA)

I have seen higher than 15 MPG on 460s but mostly in cars not Trucks.

Still waiting on some more testimonies of 460s with 15+ MPG.

 

460 and gas mileage!?same sentence hah.
My grandpa's lincoln 460 can burn 15gallons per mile

 

I'd always heard a set of 3.08s gave the best unloaded mileage with stock tires. We had a truck in NE, 460,C6,3.08s that we moved agricultural seed research equipment with. The guys claimed 12-14 solo. They took out a C6 pulling a 13,000# combine on a tri-axle gooseneck on a trip into IL (away from the normal flatlands - I don't think they were manually downshifting on the hills). I got them a set of 4.10s and instructed them to run the 3.08s until fall when they hauled the combine and switch back in the winter. We usually ran about 9-10 with the 4.10s.

Clyde pulls a 24' fifth wheel with a set of 3.55s. Average solo is ~10, best was 12.5 when in CO two summers ago. Record worst was one two-tank fill on that same trip bucking a 25 mph headwind ALL THE WAY out from MN... 5.88 mpg. Average 7-9. Best towing, a trip to northern WI with a tailwind, 10.25.

My dream setup would be a set of 3.73s with a US Gear two-speed behind my C6. Direct/OD = ~3.00, Direct/Direct = 3.73, Second/OD = ~4.30s. Best of all worlds except for the price. Ouch!

 

18-28 MPG on a Ford 460?
I wish I could get over 9. I have an 85 F250XLT 2WD with all the so called smog control crap removed. I pull a 40 FT King of the Road 5th wheel Trailer and live in a mountainous region of Nevada. I get between 6.5 MPG at 65 mph with the trailer and never more than 9 at 65 mph empty. She carries 38 gals of gas in two tanks. I can't justify the expense to my wife of adding different gearing and other modifications to try to get 1-2 MPG more.
My Guzzler has 334,000 miles+ and gets an oil & filter change every 3000 miles, battery level and water levels are checked every week, Tire pressures every 2 fillups and tranny fluid check with the oil change. Rearend every other oil change. I opted for the auto trans because of a disability. A full tune every 35,000 miles, with platinum plugs, or as needed. I went to dual glass packs for more power when pulling (I told my wife the mufflers needed replaced at 45,000 miles.) and I ride on HD wide 16" all weather tires with 85lbs of air. She still pulls great with the Holly 750CFM 4 BBL(3rd rebuild). I've tried all grades of fuel and stick with the cheap unleaded regular since I only noticed about a .2mpg difference between the top and bottom grades. She still pulls strong on the cheap stuff. I use a Prolong oil and tranny additive that seems to make her run smoother. I resigned myself to the fact that a 460 is expensive to operate, but still love my truck. My old 69 ford truck with a 360 gets 18mpg but does no heavy work. She has over 390,000 miles on her and gets the same good care. She's my baby. Ford trucks are tough if you treat them right.
I had a friend that said he got over 20mpg on his 89F250 460. I borrowed it one day and found that the gas gauge dropped faster than the speedometer increased. I never called him a liar, but, stopped listening to his stories. I enjoy the ramblins guys, but just get over the fact that good ain't always cheap. I'm 51 years old and have owned 3 trucks in my lifetime. The Chevy didn't last past 120,000 miles. Take care.

Hogman51/85F250/460/Auto/89HDFLTC

 

I actually got 9.2 MPG on my last fillup. Been driving under 65 and empty with very little wind, slow starts and infrequent stops.

 

i agree with the mentioning of 460 and gas mileage in the same sentence!!! lol!!!! but the best i every averaged was 11 mpg. i run a carter 625 with edelbrock 460 performer manifold with egr and flowmaster truck muffler. its a 2 wheel drive with 3.07 dana 61 rear end and c6 trany. tires are 31x10.5-16.5. but usually i get about 9 mpg city/highway. my rpm's at 65 mph are 2100. i have a stockland camper shell that is cab high.

i agree with those of you that say "a shoebox will only get so much mpg and that is it" i am in the process of changing my rear gears to 3.53 using the dana 61 and that will only make my rpms go up about 500 rpm more. i figure mpg wont change. i have hauled a cabover camper and a 32 ft fith wheel and a 18ft boat all at differrent times and have only lowered my mpg by 2 mpg at those times. if anyone has big secret for 460 increase in mpg i wish you would share this info with us.

leo vargas
1977 F-250 aka cricket

 

Ok, y'all. You need to consider this....

it takes a minimum amount of fuel in the air to burn

no matter what the engine size is, it will take a certain number of revolutions to go a mile

there for, a smaller engine will typically get better gas mileage...understanding that we aren't talking about pulling 5,000lbs with a GEO

The increase/decrease in weight from a car to a pickup is not significant.

I have a 1990 F250 4x4 460 that gets between 12 and 13 mpg

 

I found putting the proper thermostat back in (previously 180 deg) and changing the 02 sensor (Stock replacement) netted me back up to 17mpg with the A/C and hi rise canopy on. Keep in mind this is Imperial gallon not US. This is on BC interior roads highway only, 110kmh/65mph, not sparing the passing power

The O2 sensor made the biggest difference in mileage gain, when my mileage drops again, I am going to put in another new one

I am running a dual K&N filter setup and no cat but otherwise stock

I also found that any load seems to drop mileage to the 11/12 mpg range, but I hold the same speed as unloaded trips except the big hills

 

Old5, So what you are saying is that you get better than 22 MPG in US Measure? You must have a newer model F250 with fuel injection.
But, 22.25 MPG is still hard to swallow. Even 18US seems to be pushing it. Good luck.

 

Ok, here is the real conversion of 18 miles per imperial gallon.

1 imperial gallon = 1.2 US gallons.

old5 is figuring 18miles/imp gallon.

18miles/imp gallon = new mileage/ US gallon.

18miles/1.2 us gallon = new mileage/us gallon.

therefore, we must divide the mileage by 1.2, not multiply.

18/1.2 = 15

That sound more reasonable. A properly tuned 460 should get that. Mine is running about 8degrees advanced, and I figure that once I get back to proper timing, I should gain 1-2 MPG.

The only time a 460 might get 22 mpg is going downhill with a tailwind and the tranny in nuetral

Take care y'all

1990 F250 4x4 460 with 1 ton axles

 

OK, it's still early AM. Not quite awake. 15 does sound more reasonable, but still higher than I've ever seen on mine. No need to go through formula's.
As for your previous entry I think your a little off on your logic.
if I run at 2500 RPM on my 7.5 L F250 and my wife runs at 2500 RPM on her 3 L Taurus, I'll get around 2/3 less MPG than she will, based on Size, Weight, & Shape of Vehicles. Also, due to the larger piston capacity the 7.5 L will burn more gas at the identicle RPMs standing still. You are trying to match Apples and Papayas.
Temperature, Barometric pressure, air Intake, Terrain and Load all play an integral part in fuel consumption.
You can't say that it takes the same amount of Revs to go a mile.
If you are talking engine revs, different size engines will go different distances at the same RPMs. If you are talking tire revolutions then you are wrong again, unless tire sizes are identicle. There are too many variables to consider in determining MPGs. Transmission and rear end gearing also make a big difference. Exhaust flow needs to be considered. Also, if I ran a 5 L in my F250 I may get better mileage below 50MPH but above that and/or with a load it would go down drastically.
You needn't break things down into minute increments when explaining things. We are not morons.