Converting 6.9l diesel to a 330cu straight six???
 

ford Brothers,

I have a 1985 Ford F-250 4x4 with a 6.9l diesel engine. the engine just saw its last day.

I also have a 1985 Ford F-250 (non4x4) with a 300cu straight six.

the truck with the blown diesel is my favorite truck. it was bought from original owner and has zero body damage.

becuase of cash, I was thinking of dropping my 330 straight six into the truck that currently has the 6.9 in it.

I have heard of a few issues like:

the wiring harnesses will not match up
I would have to change out the chip in the dash (new to me)

My main concern is the 4x4 transmission.

Can anyone give me some advice on things I need to consider before doing this and are there any issues that should "prevent" me from doing this.

I love my truck and have not driven in in about two months and it is killing me.:-banghead

Any help is much appreciated.

Thanks in advance,

Having a donor truck is nice. You would need to swap the motor mount towers over and the wiring is a bit different but you could just swap that over as well. If you are really in a hurry, just lose the front driveshaft and drop in the 2wd tranny for now. You could find a 4x4 version and t-case later on if you wanted. In order to make the 2wd tranny work with a t-case you have to tear it apart to replace the output shaft and get the spacer that goes between the tranny and t-case. I'm not sure what chip you are referring to, but I haven't owned a diesel yet so who knows. You may also have to swap the fuel system components but I'm not 100% sure on that.

IIRC: The bell housing from the I6 is NOT going to bolt up to the 6.9 Diesel.

They are different.

welcome to FTE.


if the 4X4 truck is a manual trans, you will only need a bell housing, flywheel and clutch setup for the 300 to adapt it. the diesel and gas transmissions have different gearing, but it is not a big deal.
you will have to swap the wiring harness, and motor mounts. since the 85 truck still uses a carburetor, there is no computer stuff or "chips" to worry about.

Don't count on that. You might have a computer controlling that six cylinder, even if it has a carb. Look at the distributor. If it has a vacuum line going to it, then you are ok. If it doesn't have a vacuum line connection, then you do have a computer controlled engine, and all that stuff will have to move over to the new truck. A lot of work. If it were me, I would look around for another 6.9 or 7.3 and drop it in. I am partial to the diesels though. I also would look into buying a cummins 4BT and dropping it in. No wiring issues, and if you get the one from the Ford chassis truck, it will bolt in with different motor mount frame towers(the 300 six ones to be exact).

oops, i stand corrected.:o

thanks for that bit of info Dave.

i have never seen a 300 with both a carb and a computer, so i was not aware they existed.

exactly, I have a 86 F-350 with a 351 (aparantly the minority) I would give my left nut to have held out a week and bought the diesel one that came out in the next weeks auto trader. and for the same price to boot. stick with the diesel...... or trade me straight across, mine has new hubs:)

and really you can buy a 6.9 or a 7.3 idi used pretty reasonable these days