Hello all,we are starting a complete buildup on a 72 F-100 4x4 for my son in the near future.I have a 390 sitting in the shop but with the way gas prices are going my son would rather have the 300 instead.My question is will a 300 from a later year with fuel injection give us more power and fuel economy than a carb engine from the 72 era? My 71 4x4 with a 300 with carb only gets 14 to 15 mpg at best. Also what year did Ford start using fuel injection in their trucks and is it too complicated to retrofit to a 72 era truck.Thanks for any advice.
"bowties in the rearview mirror"

 

The fuel injection 300 probably won't get better gas mileage, but they upped the HP somewhere around the same time they made them fuel inejected which was 86-87.

 

If you want mileage, you're either going to have to go with an OD transmission, or use a "wimp" rear gearing (3.08 or something of the like). That gear would be a bit better for the 300-6 too, because taller gears get you into higher rpm's faster, which is exactly what you don't want with a 300-6: its powerband is 1500-3500. That's my take on it though. If you go with the 390...your mileage is never going to be acceptable so you'd be better off just going "to the wall" and using a tall gear.

 

I put a 87' EFI 300 in my 78' F150, as far as the fuel economy goes it is comparable to my carbed 300 I used to have, it might be a shade better but not much, Most of the fuel economy comes from the trans and gearing from what I can gather. the best thing about the Fuel Injection is drivability. Being able to go out on a sub zero day and have that motor fire right up is the biggest advantage to the EFI if you ask me. The wiring harness for the fuel injection is not all that complicated and can be easily seperated from the vehicle harness giving a bit of patience. other then that the only things to worry about are exhaust and a high pressure fuel system. I would rather have the efi 300 than a carbed one for daily driving anyday, but that is just my opinion.

Dave Wild,
78' F150 EFI 300
87' F150 EFI 300

 

Have you considered going diesel? If you want fuel economy and a strong truck, I would opine that a Cummins 4BT or possibly a Detroit 353 would do the job nicely.

 

Well Chevenstein, that is definately something to think about.There are a lot of good deisel motors out there.I will do some research on that as well as the EFI Dave was explaining.Do you know what kind of fuel mileage to expect from these deisels and are they straight sixes?I know nothing about deisels,thanks all.
"bowties in the rearview mirror"

 

the cummins that are run in dodges are inline six's to my knowledge (i.e. all the ones i have seen were inlines) and a buddy of mine said he gets well over 20mpg w/ his, as does another friend of mine's dad...my personal preference as far as the cummins goes...from what i've gathered talking to people that have had either 12 or 24 valve cummins (or both, in some instances) is that the 12 valve gets better mileage by anywhere from a couple miles to several per gallon, has a faster response and better performance in pulling and speed, and is just an all around better motor....don't take my word for it, but talk to other people that you might know that have diesels....also...another friend of mine had an 85 F-250 4x4 4 spd with the 6.9 International diesel, and he claimed to average 24 mpg with it, and it is a v-8 diesel....check into that, as well...and there's always the 7.3L diesel that Ford turned into the Powerstroke...not real sure how that is on fuel, but it'll give you all the pulling strenth you'll ever need, i'm sure....

just my thoughts and what i've heard people claim and say about their diesels....

MontanaFord

 

Nod, let me first say that the majority of my experience is with larger trucks (GMC 6000s, various IH trucks and a few Macks), and my opinion of how a pickup should run and drive is based on that. I think, assuming your truck is fairly light you should get around if not above 20mpg.

The Cummins 4BT is a 3.9 litre 4 cylinder inline engine. There is a 6 cylinder variant (a derivative of which is used in the Dodge) but I think it may be a bit heavy for an F100. The Detroit 353 is a two stroke 3 cyliner engine good for higher revs, good power, and lots of noise. I work with a backhoe that runs one of these (a 453, actually) and it moves the 20,000# machine around very easily. It also doesn't use much fuel and is very simple to work on. I've see a few of these in both Fords and Chevies and hope to run one in a pickup myself when I have time.

Another option, if you don't want so much noise and weight (and power), you may consider an imported diesel, like a Perkins or Isuzu. I do not have as much experience with these, and very little with them in on highway applications.

I own a Ford with a fuel injected 300I6 in it and though it is a good motor as far as gas pickup motors go, I am not happy with the level of complexity of its fuel handling system.

Whatever you do, the best thing you can do is plan plan plan. There is a _ton_ of information about this, both fact and opinion, out there and you will do well to look at it. Please keep us posted, as I think others would benefit from hearing about your project.