Ok guys this makes no sense to me or my father who has verified this and no my odometer is not screwed up. I have a 75 f250 camper special with three speed auto 2xd long bed single cab "ranger" package

Here is my situation my dad told me when he drove the truck from nc to ma for me he said he didnt need to get fuek until the bottom of Ct. I.E. he got rougly 25-30 mpg. I drove the truck to work and back today and fueled up a a hundred miles exactly the truck took 2.7 gallons (37mpg) i know this is impossible and im not complaining i also physically took of the filler neck to verify the tank was full because i didnt want to run out of fuel. The owner before me put on a holley carb and a cam that he lost the spec card to but there is no way i should be getting this type of mileage. Any ideas?

 

Fill it up and run it until it dies.

 

thats what i was thinking just thought id see if any one had any ideas as my ford fact instructors are stumped

 

What gear ratio does it have? That's impressive for ANY truck in the 70's - especially a 460. I want to know your secret

 

no idea ill pull the tag info next time im under the truck

 

Is it possible that you have the wrong speedometer gear? Try using milemarkers, googlemaps or a gps to ensure accuracy.

 

Verified with GPS and my motorcycle dead on

 

Id be happy if my truck got half that! Im with crazyeddie, I need your secret.

 

ok off the axle tag i can make out 3 54 d41a bga
8033 81 21
date of mfg 10/74
gvwr 8100
gawr fr 3300 rr 5300

vin f25jrv65718

wb 133 color mw f253 body f4 trans g axle c7
tire size 235/85r16 inflated to 70 and 75 psi f/r

Best i can get from this is that the axle is a 3.54 dana 60 with l/s diff all i got from the trans code is that its an automatic i drive smoothly but still avg between 55-75 mph but no hard stops or jack rabbit starts. I accelerate slowly enough for people who dont know the truck to think i have a straight 6 and everything except carb and cam are oem parts includeing the exhaust.

the truck turns 22-2300 rpm at 60so ideal as far as rpm range goes and the engine pulls a solid 20hg of vacum at idle and around 12hg when crusing. oil pressure is at 25psi at 2300 which is acceptable and all compression test show each cylinder to be within 5psi of each other so basically the engine is tighter than a 20 somethin nun (no offense intended) Also the aircleaner is missing the ducting so the motor ingests under hood air and avg ambient air temp outside has been between 46 and 68. Amsoil in engine trans and diff.

Best i can figure must be perfect parts for each other meshing in an orgy of power and efficency. Or mabyee i got the truck version of night rider?

 

Do you have 2 gas tanks? could be the tank selector valve isnt all the way to one side or the other... so your drawing gas from both tanks at once, but only filling one (hence the outrageously high mpg)? That would be my best guess, otherwise your the only guy here that gets to drive a dent for the price of a honda.... and defy physics

 

two tanks yes but rear tank is completly disconnected (you put the gas in the rear tank and it goes on the ground) i dont understand this at all ill have to weigh the truck mabyee the po lightened the crap out of it somehow

 

This is either baffling or incredible! Maybe both? I am really curious about the cam. What are you running for exhaust?

 

70 PSI and 75 PSI in the tires? Holy crap. Lucky ya don't have a blow out or tread separation. However, those tire pressures probably have something to do with the super-high MPG.

Still, 25-30 MPG, IMO, is still outta range with a 460.

 

Load rated e so85 is max psi

 

I'm gonna think on this one

knowing the RPM, CID, and MPG i'm guessing it is possible to figgure out out an A/F ratio.

I'm just left wondering if it is even possible to lean out a 460 enough to run on that little fuel.

maybe there is some fairy dust floating around in the tank?