I put a 1995 4.9l in a 1997 F350 4x4 that had a 5.8l and E4OD tranny. I am hoping to get 18 mpg highway what do you think? I have removed air injection no cats and use an electric fan. I live near sea level so no real hills.

Brian

 

I can see it if you are using stock tires. Big tires and jacked bodies eat into mpg bigly.

 

Hi I am keeping it stock and plan to use a tonneau cover. I love these engines nearly indestructable, I am running 2-1/2 exhaust people think I am crazy but I do not haul much with it mostly bad weather and Home Depot runs. I like the solid axle and manual hubs on the 350 too I think it will work just fine, we will see.

Brian

 

Depending on the gearing in the F350 4x4 I don't see any reason the 300 won't work. They've powered a lot bigger vehicles in the past.

But I don't know if it'll get 18 mpg. Most people think swapping a smaller engine into a vehicle will automatically give it better mileage. The issue with that line of thinking is, a smaller engine has to work harder to accomplish the same job as a bigger engine. So by doing the swap the fuel mileage usually stays the same or might even drop lower.

The F350 4x4 is a heavy vehicle. So I don't know if you'll get 18. I personally would say 15 or 16 mpg is probably more realistic. But it all depends on the entire package ( weight, gearing, transmission, engine & your driving style, etc. ) .

Are you running the E4OD behind the 300 or something else?

It sounds like you've got a cool truck no matter what it gets for mileage!

 

Of course if I have a heavy right foot then mileage will suffer but It is not a sports car and most times I will stick to 65 mph limit. I bought the truck for $400 minus the engine so I went for the 4.9l for reliability. I had a 1978 F150 4X4 with 300 and got 19mpg highway and that was carbureted and cast iron transfer case etc. I kept the E4OD getting a little old for a clutch.

Brian

 

For good mpg make sure you have heated carb air and heated intake - like the production stuff.

 

I'm not knocking your truck at all. I love the 240/300's. I'm going to be swapping a 300 into my 89 E350 extended club wagon. And it has a 5.8L that runs great( just has a bunch of oil leaks ) . The 5.8L is a good engine, just a pain to work on in the Econoline. My van is going to weigh somewhere in the 7,000-8,000 pound range. But I've got no problem giving up a little gas mileage to have a simpler, easier to work on engine.

I'm very familiar with the 78 F150 4x4's. I've got one I'm using the chassis for on my 54 F100 build. What kind of mileage would your 78 get with about 2,000 pounds in the box? I'm not positive but I believe your F350 should be about a ton heavier then the old 78 was. The D60 & Sterling 10.25" weigh a whole lot more then the D44 & 9". Then add the beefier frame, heavy leaf springs and just more stuff packed into the newer truck. The weight adds up. The EFI and OD will help the mileage some. But you still have the weight hurdle. And was the 78 a manual transmission or an auto? The auto's will have more parasitic drivetrain loss then a manual.

My whole point is just don't have too high of an expectation on your fuel mileage. It's still a great combo and should work great. I could be completely wrong. It wouldn't be the first time or the last!

If you can, post some pictures of your truck! We love pictures!!

 

The curb weight difference between your 78 F-150 4x4 and my 97 F-350 4x4 is around 1100lbs that's it really not that bad with all the plastic and aluminum and the thinner body metal on newer trucks it really is not as great as people think. Like I said 90% of the time I will be driving unloaded and not towing any trailers just going to and from work mostly highway. I will try to get some pics soon. right now I am trying to get it running I have a post on another forum here to solve the no start condition as it originally had a 5.8L and I had to change the PCM etc but I am close just need to do some diagnostics and find the problem.


Brian

 

You will come closer to obtaining your 18 mpg goal if you limit your speed to 55-60 mph.

 

What are you doing with the EFI? a bit TL;DR ... Are you going to reprogram the 5.8L EFI or use the 95' wiring and EFI?

 

I got the complete harness with the 4.9l engine and I got a PCM from a 93 F-150 that had the 4.9L and a E4OD tranny from a junk yard. I also got a brand new radiator that the guy just put in the F150 I got the engine from as well as an excellent Y pipe and new muffler that was also on the 4.9l. I eliminated the air pump and piping and no cats I do not need them on this truck in my state and am also running an electric fan.


Brian

 

How did the mpg turn out?