Hi all, this is my first post here but I've been lurking for a while. I've got an 83 e-150 cargo that I've been restoring. It has the 300 straight six in it.

So far I've rebuilt the carb, replaced the vacuum lines and fuel line, replaced the radiator, heater core, and all coolant lines, replaced plugs, wires, cap, rotor, coil. Its running like a champ. there's a bit of stutter at idle speeds but I hear that's pretty normal for this engine.

Right now I'm getting around 16mpg. Is that about normal for this van? Anyone else with the same engine have any numbers to compare?

 

I've never owned a straight six, or even an E-van, so take this for what it's worth:

A quick survey on Fuelly shows your fuel economy to be pretty good:

Ford E-150 Econoline Mileage | Fuelly

There's not much data to go on, but yours looks pretty good against what I'm seeing there. The newer generation engines were never rated for any better than that. The V6 in a 2002 Econoline was rated for 16 highway.

 

There are a whole lot of variables that will ad or take away fuel mileage. The vehicle weight, engine tune & condition, the type of transmission, rear end gear ratio, tire size & air pressure and driving style just to name a few.

I've seen poor running 300's get as low as 8-10 mpg. But I've also seen them get low to mid 20's. But in a fairly light vehicle ( aka half ton truck or van ) mid to high teens is a good average.

 

if you have a 3spd auto trans you are doing awesome! 300 6cyl will run forever but power and fuel economy aren't its finer points unless to change intake/exhaust to let it breathe, and remove the dual square logs.

 

Thanks guys. I guess I should be happy it's running nicely. I'm a bit sad there isn't much more efficiency to be found though.

I am about to pull the mechanical fan and replace with an electric. That should increase mpg a bit.

 

a dual plane offy intake and a 500cfm 4barrel along with a header or a pair of efi exhaust manifolds will increase your fuel economy and power more. but it depends how many miles you are putting on it and what you are using it for to make it worth while for you.

 

I started looking into replacing the carb when it became clear I needed to work on it. Honestly I have a lot more reading to do before I'd be confident I was making the right swap. This is the first automotive carb I've ever monkeyed with.

500 cfm 4 barrel seems like a bit much for this engine though. At some point don't you start losing velocity and efficiency?

 

If the stock carb is running OK, I don't know if I could justify something as pricey as a manifold and carb change...it might increase horsepower from 140 to 144 but it will not change the basic character of that engine and it will never pay back the initial investment unless you get used parts cheap or free. The 300 is not comfortable revving much over 4000-4500 rpm's...

I bought a new '78 F100 pickup with the 300 and the 4 speed manual OD (and a 2.75 axle). Final drive ratio was 2.18 and almost useless except on flat land. It would get 22-23 mpg on the freeway but that was in the years of the 55 mph speed limit. Engine would be turning about 1600 rpm's at 60 mph. I put about 100k miles on that pickup before I moved over to vans in 1986.

Your mpg sounds about exactly right for what you have (larger frontal area and way more weight than my old pickup) without an overdrive transmission. You might get some minimal mpg improvements moving to low rolling resistance tires or doing a bit of aero modification like adding a front chin spoiler. Most vans built in the 80's got 12 mpg...

Good luck,
George

 

Do you think a 500cfm carb would be too large for a 302 V8? The 300 has larger cylinders then the 302 V8 does. The 300's cylinders are the same size as a 400 V8. The 500 is not to large. They run quite well on a 300.

But if you are worried about the 4V look into swapping on a Autolite 2100 2V carb. These came stock on Ford V8's in the 60's. They are simple, reliable and perform well. I'm going with two of these on my 300 that I'm swapping into my E350.

But like 68Mercury250Ranger mentioned. I would up from your stock exhaust manifold to a pair of EFI dual exhaust manifolds. These are basically a pair of cast iron shorty headers that came on all EFI equipped 300's (1987-97 ) . Not only will they increase your power they will also help make the engine more efficient.



I'm sorry but the manifold & carb swap are worth a whole lot more then 4hp! If you don't think it will change the character of the engine. That just tells me you've never driven a modified 300. The stock 1V carb is a major restriction! And so is the stock carb exhaust manifold. Think about running a marathon while breathing thru a straw!!

The 300 will rev over 4500 too, especially if it's a modified one. Ever hear a 300 turning 7,000 rpms?? This one belongs to a fellow forum member Frenchtown Flyer.

 

Ted, the 4hp was kind of tongue in cheek and the gain will be more but it's not gonna help the van much. I have not driven a modified 300 and have no desire to unless I someday build a funky rat rod with a 300 in it I bought my F100 brand new in 1978 with the six and performance was pathetic with the gearing on it so adding HP at higher RPM's was not gonna help. In normal use, my 300 spent its life between idle and 3000 rpm.

In the early 70's, I had owned and raced a couple 426 hemi cars including a 12.5:1 crossram hemi with a gear drive. And I also had a bunch of big block muscle cars. While I owned the F100, I also had a Corvette. So modifying a really slow truck to be slightly less slow was not on my agenda.

Here's a nice modified van that's worthwhile.
Take care,
George

 

Don't loose sight that its a 300ci air pump. Bigger than a 289 V8.

 

Not really, it's the wrong brand to worthwhile.

 

Ford vans are definitely tougher, but the unit body Chevy shortie was significantly lighter. I did have a couple GMC vans mixed in with my Ford vans and trucks.

And hell, I've defaulted into Dodge minivan...although 283 hp out of 220 cubic inches (3.6 Pentastar) is pretty darn impressive especially without direct injection.

I've met Jarvis and he's a really nice guy. And getting into the 9's with a full sized van with a small block is really a pretty good accomplishment. There are so many vans and trucks that make a lot of noise but would be embarrassed if they actually had to show a time slip.

Sorry to the OP for the thread drift but I love Ford vans and I really like the 300 inch six although in 2016 it's not state of the art in power or efficiency. But it is a great, tough truck motor. Besides putting 100k on one in my pickup, I rented a 12' F350 U-Haul box truck for a big house move in the 1970's and it was slow when loaded but could hit the speed limit. I opened the hood and there sat a 300 inch six, with a 1 barrel carb. Holy cow...I was expecting a 360 V8.

George

 

In 2002 a friend of mine with a 95 E150 I6 C6 transmission went on a trip following someone with a 2001 E150 5.4 driving 75 MPH, identical vans besides the newer one having a high top, they both got the same MPG. BTW the 2001 is on it's third engine, guys hard on it, and the 96 registers 340,000 miles yet has been driven 2 years without a speedometer, the electronic device quit on it, he has quit driving it, complains it's sluggish, which I keep telling him, have the injectors replaced, they are the originals.

 

1 barrel carb and log manifolds on the 300 6cyl were meant for industrial application, under 3000rpm operation with a steady load. 500 cfm edelbrock, dual plane intake and a pair of shorty efi headers and your hp would probably dial in 100hp increase from stock form, even more if you put an aftermarket set of timing gears in it. that would still be a very reliable /drivable form and increase your fuel economy and pulling power>>>torque. this engine has so much potential that was only partially tapped when they put efi onto it. UNDERAPPRECIATED !!!!!!!