hi fellas i have a 1984 f-250 with the 6.9 diesel in it and it is right now under complete restoration. i am having trouble deciding what to do about the motor and have recently been flirting with the idea of dropping in a 460. does anyone know where i could find more info about doing this or better yet has anyone done it? i found a place that sells the motor mounts to do the conversion but i still have many questions like will the 4 speed manual still bolt up? what kind of wiring dilemmas am i getting into? will the rest of the drive train work out like the transfer case, drive shaft length, and do i need new rear gears? any help would be greatyl appriciated.
thanks guys,
Jsarver11

 

Ouch going gas.......... Well, the gearing for the trans is different you have the T-19. You can change the bell housing but better of just getting a trans off a 460 rig (T-18) from that vintage. The wiring harness is different firewall to engine you should be able to take a donor wiring harness same vintage and plug it into the original firewall mount. They were wired in the cab for both. The 460's from that era were loaded with all sorts of smog crap. Might want to look into the 70's pick ups for a less complicated engine.

If it was me I would put a new diesel back in and done right you can leave a 460 in the dust.

 

It so happens I converted an '85 with a 6.9 to a 460 gasser last winter. (Not my choice, it was what the owner wanted.) The physical aspect of the swap wasn't too bad. I did swap complete engine/tranny/t-case in with the gasser but the 6.9 uses an adapter plate that bolts up a tranny or bellhousing with the 460 pattern. (At least, the one I worked on did. It was auto and used a 460-pattern C6, I presume the manual is the same way.)

Both trucks were the same wheelbase (regular cab) and I encountered no driveline problems. In your case I would leave the tranny/t-case in the truck and just swap the motors. But I'm not really familiar with the tranny differences for manual trans...

The wiring...that's where the fun began. Get yourself a good wiring diagram for both the gas and diesel versions of your truck and rely on them. In fact, I'd get a Helms EVTM to work from. (I wish I had!) You'll find that most of the electrical components related to the diesel and mounted on top of the right inner fender will need to go, you can leave the dual battery system in place and add an isolator or ditch it and go to a single battery (I did, but kept the diesel's 100 amp alternator and installed it on the 460.) We went with an electric fuel pump on the 460 even though we used a carb so I swapped over the gasser's fuel pump relay and inertia switch setup.

You'll need to wire in an ignition system which isn't too bad. At one point I looked at swpping the entire wiring harness from the gasser donor truck into the diesel, but it looked to be even more of a nightmare than just adapting the diesel harness over as it goes through the firewall on the pass. side and up under the dash to the fusebox rather than having a separate engine compartment harness that just unplugs, as I'd hoped to find.

Pleas feel free to aks me any other questions about the swap and I'll answer them to the best of my ability...many of my memories of the ordeal have been blocked by now...

 

right now i am looking at take a 460 out of a 85 250 and droping in a diesel the guy wants a diesel engine and dont have the money to just buy a new truck he is disable and we are looking for a diesel engine now to do a swap