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Converting a F250 into a 1/2 ton

I put a 460 in my 66 F250 and now wanting to see if I can squeeze a little more gas mileage out of the beast since gas has gotten more expensive since the project started so the cheapest way is to convert to a 1/2 ton,since I have a 78 F150 that will be donating the front suspension and have a 9 inch from a 67 to 72 f100 being removed in a local junkyard this winter I will be doing the conversion. I probably should have put a 351-W and AOD in it but could not pass up a fresh 460 and C-6 for 500 dolars so it went in,I thought I was going to do more serious hauling but I just want to be able to drive it on long trips so a 1/2 ton is what it will be when I am done and will thgrow the original suspension in the shed in case I want to put it back.
 
With a 9 inch instead of the Dana 60 I can play with gear ratios much easier,it has 3.54s now but going to try 2.75 or 3.00 which the 460 should have enough torque so it wont be bogged down too much. It also needs tires so 15 inch will be a little cheaper then the 16 inch truck tires.
 

DNFXDLI

The Token Canadian
Staff member
If mileage is your primary concern, a truck is not the way to got go about IMO.
I realize what you are saying about swapping out the carriers on the 9''.....but it seems a great deal of work.....just swap the gears out on the 60.
 
I wish I knew how expensive it was going to be to put a overdrive trans behind a 460 before I bought it or I would have got a 351-W instead,it got 13 on a small trip last fall and thinking with more highway gears and some tuning I might be able to get it in the 16 to 18 range and that would be good enough for me. The 3.54 gears in the Dana 60 are the best I can get and need better and it should take me a week to convert to 1/2 ton and much cheaper then to put a o/d trans behind the 460,I think there is a vibration coming from the rear end so I think something in the limited slip parts is wearing out so this winter its going to become a 1/2 ton.
 

Sparky83

Virginia Chapter member
5,566
219
Norlina NC
With a 9 inch instead of the Dana 60 I can play with gear ratios much easier,it has 3.54s now but going to try 2.75 or 3.00 which the 460 should have enough torque so it wont be bogged down too much. It also needs tires so 15 inch will be a little cheaper then the 16 inch truck tires.

i wouldnt do anything under 3.25 gear for r&p if you do go to the 9"... anything below that and your engines going to have to work harder just to get you going... harder it works the more fuel your going to be burning. yeah itll lower your rpm's for street/highway going to that low of a gear.. but youll also be killing any acceleration you have as well.. and if you ever had to haul or tow something it would make it just that much harder on the rest of the drivetrain..

I would stay with the larger tires though.. the longer circumference of the 16in tire will allow you to travel further on 1 revolution than you would for the 15in. the smaller diameter tire would be counter productive to what your trying to do with the R&P change since your powertrain would then have to turn that smaller tire more revolutions to cover the same distance as the larger one did with 1.

if you really want to help with economy.. if your truck does not have an OD transmission i would suggest swapping one in that does have OD. itll help you out on the longer highway trips than anything else.
 

73F100Shortbed

That's how we roll!
5,937
320
NJ
Save your money and put it toward gas. I know gas is expensive but sounds like a lot of time and money to save a few dollars. It'll take quite awhile to notice a huge difference in savings. Plus going from an f250 down to a 1/2 ton is like trading in a super model for a big girl :D
 
Picked up the 9 inch from the junkyard today,it took them a couple weeks to get it out but I was in no hurry. I have the front suspension but can not cut up the truck at this time so I will have to find another since I plan on doing the swap before it gets cold,the 9 inch has 3.70 gears which is a little more then I want so the 3.00 gears will be going it.
 

Sparky83

Virginia Chapter member
5,566
219
Norlina NC
btw.. just to let you know... on the mustang forums guys have compaired mpg when chaning R&P gears... when they went from 3.55-4.10's all they saw for a difference of mpg was 1mpg on the highway... they said city there wasnt any difference for them
 
The mustangs most likely had o/d which I do not,I would leave it a 3/4 ton if I could put a o/d trans behind the 460 but its cheaper to convert to a 1/2 ton. Its going to cost a couple grand minimum to put a o/d trans behind that motor and I will have less then 500 in it doing it my way.
 

Sparky83

Virginia Chapter member
5,566
219
Norlina NC
The mustangs most likely had o/d which I do not,I would leave it a 3/4 ton if I could put a o/d trans behind the 460 but its cheaper to convert to a 1/2 ton. Its going to cost a couple grand minimum to put a o/d trans behind that motor and I will have less then 500 in it doing it my way.

some do some dont.. it didnt matter if they compared autos or manuals.. they all saw the same. wasnt wanting to talk you out of doing it. just wanted to let you know that the gearing alone your not going to see much from it.
 
I am just trying to get it more highway friendly and ride a little better,I should have bought a 100 but this 250 was much cheaper so its all I have to work with and not going to start over with another truck. I spent about 4 years doing the body work and can not afford to buy another that is done so this one is getting converted,I wish now I would have got a 351-W and AOD but when I bought the 460 gas was around 2 dollars a gallon so I am going to work with it. It got 13 on its last trip and I am going to see if I can get it up to around 16 but if it does not happen I will end up with a truck that is more highway friendly and I will not have spent a ton of money trying,not including new tires I should have about 500 dollars in converting the suspension over to a 1/2 ton and what ever I get out of the original parts will help with the new tires. I was planning on hauling a bunch but the more I think about it if I ever do I am going to buy a 90s F250 that has all the creature comforts plus overdrive when the time comes.
 
What about converting to propane ??
 

Sparky83

Virginia Chapter member
5,566
219
Norlina NC
Picked up the front suspension from a 77 today at the local U pull that was having a 1/2 off sale,kind of forgot I picked up a set of 8 lug disc brake beams that was set up for a front sway bar so I have to get them apart so I can get the sway bar brackets off and install them on the 1/2 parts. I hope to get taking the 66 apart in a couple weeks as I want the conversion done by early october.
 
Got the sway bar brackets off the 3/4 ton beams and now trying to get the 1/2 ton beams apart,the nuts under the spring wil not budge so more soaking with PB blaster. I was hoping I could use the 3/4 ton beams but they have larger king pins,I had to cut the nuts off those beans so I might have to do the same with the others but trying to save the bolts.
 
I think the new kingpins in the 66 beams are the same as the 76 so apart they come this weekend and will find out for sure,if they will work it will save me a hundred dollars and I hope I can get the bushings out of the spindles without destroying them.
 

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