Will a 89 7.3 work in a 84 truck
 

I have a 84 f250 6.9 but the 6.9 is bad and I have a chance to pick up a 7.3 out of a 89 f250 and if it will what is all involved

i forgot to say that the 7.3 is auto where the 6.9 is a 4 speed i think i can just swap the clutch over to the 7.3 as its brand new. now do i need to put the wiring harness from the 89 into 84 or will the stock wiring harness work on the 7.3. any help would be great

Ok come to find out its not a 89 7.3 but a 91 7.3 turbo. So I've been reading a lot and found out that a 7.3 is basically a bolt in and I just need to swap a few things from the 6.9 over to the 7.3 but everything I've read is non turbo to non turbo. Is it still a simple bolt in or because of the turbo it just got complicated? I really hope some one can help.

The 7.3 has a different glow plug system than the 6.9. They use different glow plugs and controllers. You would be better off converting to the 7.3 setup if you could or just put your 6.9 glow plugs and harness on the 7.3. You should be able to use the flywheel and clutch off the 6.9. Are you getting the turbo as well?

Ya I'm getting the whole truck it's been wrecked but it's all there in the shop now pulling the 84 apart and the 91 is getting delivered today sometime. So I should have the 6.9 out today so I can start on the 91 tomorrow. Just hope I'll have it done by sunday night as I gotta be at work at 430 in the morning monday. So any and all help will be used. Thanks for any and all help.