Hoping somebody can answer some questions for me. I have 1983 f-250 4x4 with t-19 4 speed trans. and 6.9 IDI engine. Well the engine threw a rod and lunched at 149000 miles, this truck is in very nice condition and just cannot scrap her so I am looking at a used 1991 7.3 IDI engine with auto trans., question one is will this engine drop in and bolt up to my existing bell housing and can I use the 6.9 flywheel mounted to the 7.3 and use 6.9 starter motor? question two is the glow plug system, what will I need to change to make the 7.3 system work in my 1983 truck? question three is the injection pump from the 6.9 which was rebuilt along with injectors, will it work on the 7.3 engine or are they different fuel deliveries?

 

will this engine drop in and bolt up to my existing bell housing?
yes.

can I use the 6.9 flywheel mounted to the 7.3?
your keeping the manual i take it.yes use your trans and flywheel.

and use 6.9 starter motor?
yes.use whichever starter you prefer.

what will I need to change to make the 7.3 system work in my 1983 truck?
wire in the system that's on the engine.replacement plugs will be zd9 now.

is the injection pump from the 6.9 which was rebuilt along with injectors, will it work on the 7.3 engine?
use the fresh parts.they will work just fine.

merry Christmas.

 

so what you are saying with the glow plug system I need to get wiring and components from 1991 truck with the 7.3?

 

you don't need too.but its a much better system than the older one.it would be silly to swap anything old from your 6.9l over.
while your at it,rip out your water trap and bypass it.remove the fuel filter and use the one in the newer truck.the 7.3l has a better (though still failure prone lol) water/filter combo setup.

 

this 1983 used the glow plug controller that threaded into the block into a water jacket behind the air cleaner which was only used in the 1983 and modified after because of constant failures, and would burnout the glow plugs. what I did was interrupt the ground wire and run it through a push button in the dash so my glow plugs heated as I pushed the button. so I am thinking I am going to need more of the components off the 1991 solid state system that it used.

 

will passenger side exhaust manifold on 1983 6.9 fit 1991 7.3?

 

yes.
6.9l and 7.3l idi's are the same basic engine.the 7.3l's got some updates like better rocker arms,better external gp system and fuel filtration,more power due to more cubes,larger head bolts but,for the most part it's just a bored out 6.9l.
when things totally changed is mid year of '94 when the 7.3l then became a completely different engine and nothing really is interchangeable.

some of the early 6.9l's had a weak point on the block around the block heater.if you used it,it could weaken or crack.might be why she threw a rod out the side of yours.no worried with the 7.3l's there.just study up on proper coolant maintenance.though talked about a lot, cavitation reports very rarely comes up on the forums.probably because most know to keep treated coolant in 'em.

 

thanks guys, I am finding this forum thing to be extremely helpful. I pulled the trigger and bought a used 1991 7.3 to replace the 6.9 that failed me and I hope it all goes together good. THANKS!!