5.8 gas to 6.9 IDI in an '89

Made a deal with my neighbor who just wants a 2wd diesel to drive for his business to save fuel costs running blended waste oils. The deal is I got a DRW conversion 4wd gas truck for parts. Going to move front and rear axles between it and my CCLB truck so I wind up with 4wd DRW and he'll have a 1 ton diesel by installing my old but good 6.9 and T-19 4spd into it. I had blown a head gasket in it so I elected to just put in a good 7.3 IDI that I had in my truck so now this engine is on a stand and back together. Anyway getting it to run should be rather easy. Gonna use push button glow plugs. I think the hard part will be wiring up the gauges and dash. I got a diesel cluster so it will have a tach etc. I'm not sure about the frame engine mounts. I've got the engine side with the 2 bolts that go into the frame but there's plates on my frame there that they go into. Haven't looked at the 5.8 truck yet to see if there's a difference. Anyway I figured I'd post here as I get various things done so that other's might benefit.

I did the same exact thing your working on a looong ways back (TDS days)

I don't have any better pics but this is what I remember doing. You need those plate mounts from the diesel and they should mount up with at least 2 bolt locations on the gasser frame (enough to locate them to drill the remaining holes) You also have to cut off the bit mount that its on the back drivers side of the front cross member.



If I remember right the passenger side bolts right up no problems. Drivers side is the cutting and then I think just 2 holes to drill.

This is as far as I ever got with the conversion though so I don't know too much on the wiring, but from what I remember reading about it that it was really simple, even simpler if you are going to do push button glow plugs.

Thanks man, picture says a thousand words. I can clearly see the part that needs cut out.

As for the frame side, I've got all the tools I need to fabricate something if I can't find a diesel in a local wrecking yard. I think what I can do is measure on my truck the engine to frame in some key points then hang the engine in place and fabricate up the frame brackets.

Wrong section but I think the real fun will be 4wd to 2wd front end conversion. I don't think anyone has ever done that since most would go the other way. I sure wish I could have found a 4wd CCLB to start with LOL.

I will see if I got some more pics when I get home. For the motor mounts if you have the diesel motor with mounts that go down to what is pretty much just like a plate then you have all you need. The gassers have big (long/tall) mounts to bridge the gap between the frame the the motor, while the diesel mounts are relatively small (short) I think when you say "but there's plates on my frame there that they go into" those are the mounts and will bolt right up to the gasser frame with simply 2 drilled holes and cutting off that rear portion.


For the suspension it seems the rear shackle mount should bolt up easily, I just wonder about the front shackle mount that goes inside the frame horn. Maybe a drop shackle kit bracket could bolt right up to the 2wd frame?

Also the trans cross member MIGHT give you a problem, I know it is different between F250 and F350 trucks so I wouldn't be too surprised if it is different between 2wd and 4wd. The problem comes with the droop on the drivers side. I had installed a 4" lift on my F250 based truck and found the front drive shaft was hitting the cross member. To fix this I needed to get an F350 crossmember and a double cardine joint for the T-case (stock F350 setup)


Like I said I know I got more pics at home, not sure if I still got the ones that will help you out but I'll check.

don't have too many pics but I do have this one of the diesel front cross member showing where the motor mount plate bolted to the frame. You can see the 2 holes towards the top and then the 2 lower ones (surrounded by the grime) If I remember right the plate wraps around the backside and might bolt in there too but I am not 100% certain.

Awesome, thank you! I've been thinking I might as well just loosen up the 7.3 in my truck and measure and copy that plate assuming I don't find one in a boneyard somewhere. Having these pictures sure helps.

Always glad to help out!! Wish I had more that would help you but I never got passed the rolling chassis stage. Best of luck with the build and I'll make sure to keep checking in on this thread.

Well the only fly in the ointment is the undetermined start day. I have the other truck in my possession but no title yet. I bought it from a friend who bought it out of state and he's been having a heck of a time getting the title in his name so he can transfer to me. I was hoping to start this weekend. Maybe instead I should squirt some penetrating oil on all the relevant hardware on both trucks.

Well I've got a clear title, both trucks side by side, and some time on Sunday to play around. First thing to do is make a list of all the bolts I'll need to replace the rivets I'll be grinding out.

On a gas to diesel swap, I've read somewhere that the coating on the tanks is different for gas and doesn't play well with diesel, is there anything I can do to strip that coating off? I don't want to buy two new tanks on top of having to buy senders.

I started a new thread in the project log since this involves much more than a motor swap.