i have a 400 V8 in my 79 f-250 4X4 thats on its way out. my driving demands good torque, not horsepower, and good reliability. i have heard that the ford I6 is a very good motor, with lots of torque at a low rpm. is this true? if it is, i would like to drop one in when my engine goes. is it a straight drop in with an NP435 tranny? and will the engine be able to keep up with the weight of my F-250? like i said, horsepower isn't all too important to me, just as long as i can reach my top speed of 75Km (life with a 4 speed). any opinions, or facts, would be appreciated. thanks

 

I have never heard of someone going to a I6! I think they are great engines and they do put out good power and are very easy to work on - however - if I were making a change I would just go to a 460 - they are real torque monsters!

 

it would be alot of work. it'll move your truck, but it'll take more effort than to move my f100. there really good engines and have low end torque. the choice is yours.

 

just to reiterate what is already said,
i have heard they are very good engines. any farmer you ask says they are great for torque. they are high mileager's and very easy to work on, but i think you will have a bit of work cut out for ya if you go with the switch, if im not mistaken i think youll have to swap everything! good luck!

--nick

 

I get 18mpg in my 300/6 + Lots and lots of torque- Very smooth running motor (seven main bearings) Most engines run forever- 300,00 is not uncommon from all the testimonials I hav read. With a bit of work you can get HP out of them also. 4bbl, headers, 240 milled head with 1.94/1.60 SBC valves, port, polish and 270° cam- Getting 300HP out of these engines are is not that difficult. Just remember the 300 six uses the ford smallblock belhoushing and different motor mounts. Just find a differnt bellhousing and mounts and your all set. The motor pulls my crewcab very nicely and I do alot of highway travel so I love the milage- Getting ready to install a beefed up AOD 4-speed auto.

Glenn

 

i wouldn't personally go from a v8 to a 6. i had a 6 in my 78 f 150, the punishment i put it through wouldn't kill it! also my friend owns a body shop, his 85 ford wrecker has a 300/6 in it, it will snot, and not go to fast pulling something heavy, but it will pull anything! my gas mileage was like 10/14 for my 300. thats the only part i miss in my 78 f150 351M. but i'm sure there's ways you can get the milage from your v8!

Goose

 

I had a f-150 extended cab long bed old farm truck beater with a 300/4spd and a 3.90 rear end. Loved it, drove nice, rode smooth at 65-70 mph, the farmer I bought it from pulled a medium size stock trailer, said he would slow down on some hills, but did fine. I think the 300 is the best engine ford ever built.

 

Gord,
You never said what gears your running. The 300 CID six can burn a heap of gas if your on the highway with 4.10 gears. I'm pretty sure you've got a granny in that four speed which means you could still be getting 12-15 MPG after its all said and done.
The 300 I6 is a small block and you've got a big block. That means different tranny bell housings and motor mounts. Just get what you need from the junkyard. There are plenty of 300 I6 out there. The 300 will be the cheapest one to buy and maintain and insure. Probably the smartest choice.
KingFisher

 

My 240 got 17mpg with 4.10's, I should just rebuild it and use some turbo's....

 

 

ok, so well you are all telling me that the 300 is an excellent engine...but there will be some difficulties. i do have 410 gears i'm pretty sure, so gas miliage will never be great, but atleast would be better with an i6.

different motor mounts? of course. but it should bolt up to the tranny right? the 400 is a small block, not a big block, so shouldn't it fit up right? i don't know, i've never done a swap.

thanks guys. if it doesnt turn out to need any expensive adaptions, i will do the swap (when the time comes for a new engine, anyways).

 

No, the 300 I6 IS a "small block". The 400 is sort of techincally a "small block" but it belongs to the 385 engine series. It's pretty much a "small block" with a big block bellhousing pattern.

 

>No, the 300 I6 IS a "small block". The 400 is sort of
>techincally a "small block" but it belongs to the 385 engine
>series. It's pretty much a "small block" with a big block
>bellhousing pattern.


351C/351M/400=335 Series
370/429/460=385 Series
289/302/351W=Windsor series
332/352/360/390/406/410/427/428=FE Series

The 400 has a couple of bellhousings

 

Gordon,
Another coincidence is that the 400 and the 300 are both 4" bore by 4" stroke, so if you can live with 6/8th's the displacement (75%) you'd probably be OK. As far as pieces necessary to make this happen here's some stuff I can think of right off my head, assuming non-EFI and non-serpentine:
1.) Engine frame mounts from FE V8 or 240-300 six, 73-78 F-series. Once you have the engine hanging in there you will see that some of holes are already drilled. Line up the existing holes and drill out the remaining. Note: 79 f-series 300's for some odd reason use a different matching pair of frame mounts and motor mounts, which also would work if you happen to find some.
2.) Six/small block bellhousing as mentioned. These are very common. If you were close I'd give you one just to help clean up my garage.
3.) I'm not sure if the Z-bar on your clutch linkage is shorter than for a small block.
4.) Accessory brackets for six. These you are going to have to scrounge as needed. All have alternator, some have air pump, a few have AC, but for some reason the hardest thing to find is the power steering bracket. E-series vans are a good source.
5.) Cable throttle setup for six in F-series. Lokar also makes cables.
6.) Radiator lower outlet. The 300 lower hose is on the opposite side. Have outlet in radiator moved, or I've seen people route two coupled hoses underneath the engine to the radiator outlet.
You'll still have some minor wiring, and an exhaust down tube. If I think of anything else I'll post it.
Good Luck,
Brett

 

Gordon,
I suddenly snapped to that it's a 4x4. Everythings the same except I cannot remember if the FE frame mounts are usable. Somebody will jump in and correct me.
That's what I get for posting after midnight,,,,half-asleep.
Adios,
Brett